This is why nuking a hurricane will not work, Mr Trump


Liz Ritchie-Tyo, UNSW

President Donald Trump has reportedly suggested on more than one occasion that the US military explode nuclear bombs inside hurricanes to disrupt them before they reach land.

As reported in National Geographic, this is not the first time a suggestion like this has been made – although Trump now denies having said it.

On the surface, it would seem like a simple solution to the devastation that occurs in the US each year during the hurricane season. However, there are several problems with this idea.




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What is a hurricane?

Hurricanes are low-pressure weather systems covering an area of more than 500,000km². They form over warm tropical oceans, which are their primary energy source. The low pressure at the centre of the hurricane – the eye – draws in the surrounding warm, moist air. This air then rises and condenses into deep thunderstorm clouds surrounding the centre – the eyewall – and also in cloud bands spiralling out from the eye called rainbands.

As the air is pulled into the eye, Earth’s rotation causes it to spin cyclonically – anticlockwise in the northern hemisphere and clockwise in the southern hemisphere. The continuous supply of air into the deep thunderstorms surrounding the eye allows the hurricane to intensify until it reaches a steady state of equilibrium with the oceans and the environment.

Would a nuclear bomb put a dent in a hurricane?

The average hurricane can be likened to a very inefficient heat engine. As the warm moist air rises, it releases heat energy through the formation of clouds and rain at a rate of about 5.2 x 10¹⁹ joules per day. Less than 10% of this heat is then converted into the mechanical energy of the wind.

To give some perspective of this energy, the heat released in a hurricane is equivalent to a 10-megatonne nuclear bomb exploding every hour. This energy is also on the order of the global energy consumption in 2016, according to the United States Energy Information Agency.

It seems unlikely that exploding a bomb in the hurricane would make much impact on such a powerful weather system, and it is impossible to run controlled experiments to determine whether it would.

Not to mention that there could be shocking effects from the fallout of radioactive material from such an explosion. These materials would be transported widely via the trade winds through the lower levels of the atmosphere, and potentially around the entire planet in the stratosphere – similar to the effects from the volcanic fallout from Mount Pinatubo in the Philippines in 1991.

Have people tried to stop hurricanes before?

There have been previous attempts to modify the impacts of hurricanes. Between 1962 and 1983 the US government funded experimental research on hurricane modification known as Project STORMFURY. The fundamental premise was, because the potential of damage from hurricanes increases rapidly with the hurricane’s wind speed, a reduction in wind speed of as little as 10% could make a large difference in the impacts when hurricanes reach land. By seeding the air outside the eyewall with silver iodide, a chemical used to seed clouds, it was thought a new ring of thunderstorms may develop outside the eyewall – robbing it of energy and weakening the hurricane.




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Modification was attempted in four hurricanes on eight different days. On four of those days, a 10-30% reduction in wind speed was measured. The lack of response on the other fours days was initially interpreted to be the result of faulty execution of the experiment, but was later attributed to an imperfect understanding of the microphysics of clouds in hurricanes.

Successful cloud seeding using silver iodide requires that supercooled water droplets freeze onto the silver iodide seeds.

Recent observations show hurricanes have too many naturally occurring ice crystals and too few supercooled water droplets for cloud seeding to be effective. So any change in hurricane wind speed observed during the STORMFURY experiments was almost certainly due to the natural behaviour of hurricanes rather than human intervention.

Although Project STORMFURY was abandoned, the hurricane observation program is still run under the Hurricane Research Division of the National Oceanic and Atmospheric Administration (NOAA). The original aircraft used in Project STORMFURY were replaced in the 1970s by WP-3D aircraft, which still reside under NOAA and are operated by its officers.




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The observations collected by these aircraft continuously over a period of more than 60 years has helped improve hurricane forecasting. Furthermore, these observations have allowed researchers to develop vital insights into the structure, intensity, and physical processes of this most destructive of natural phenomena.The Conversation

Liz Ritchie-Tyo, Associate Professor, School of Physical, Environmental, and Mathematical Sciences, UNSW

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The stubborn high-pressure system behind Australia’s record heatwaves



File 20190124 135136 p47dl4.jpg?ixlib=rb 1.1
Parts of Australia have broken multiple heat records over the past week.
Vicki/Flickr, CC BY-NC-SA

Steve Turton, CQUniversity Australia

If you think the weather this month has been like Groundhog Day (albeit much hotter), you’d probably be right! Much like a stuck record, weather systems seem to have stalled over most of the country.

Brisbane residents are questioning the lack of rain, storms and heat. Darwin has just endured its second-latest monsoon onset on record after weeks of heat and humidity. Interior towns and cities have experienced significantly hot weather with a number of new maximum and minimum temperature records broken, along with records for consecutive days over 35℃.




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Perth has largely escaped the heat so far this summer, while Sydney and Hobart have had a mixed bag. Coastal sea breezes have tempered conditions in the south and southeast of the continent. However, heatwaves are forecast for Melbourne and much of the southeast, with the arrival of strong, hot northerly winds. This will also bring extreme or severe fire weather conditions in many areas, including Tasmania. Adelaide, meanwhile, has sweltered through the hottest day on record for any Australian capital.


Bureau of Meteorology

These weather patterns across the country are largely due to a stubborn blocking high-pressure system that has remained over the Tasman Sea since early January, affecting weather on both sides of the ditch. This type of strong high-pressure system typically forms further south than usual, and remains almost stationary for an extended period, thus blocking the west-to-east progression of weather systems across southern Australia.




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Sometimes, these blocking highs position themselves over the Great Australian Bight. They can occur at any time of year, and can stay in the Australian region from several days to several weeks.

This schematic shows a ‘blocking high’ preventing weather systems moving across Australia.
Understanding Climate Change in Australia report

Winds rotate anticlockwise around high-pressure systems in the Southern Hemisphere. On the northern flank of the blocking high, southeast trade winds have been affecting northern New South Wales and eastern Queensland due to a persistent ridge of high pressure. These winds have been largely cool and dry, with only the far north of Queensland experiencing significant showers. The ridge has kept the inland trough further west over inland NSW and Queensland, preventing normal afternoon thunderstorm activity in the inland, and adding to the woes of the extended drought.

Cool, moist weather from the Southern Ocean is being displaced southeast by the blocking high, resulting in prolonged continental heatwaves and lack of rain. On the western flank of the blocking high, hot dry northerly winds from the arid centre are pushing through South Australia and Victoria, generating heatwave conditions.




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Across the ditch, cooler and drier southerly winds are affecting much of New Zealand. Only the southwest of the South Island is getting any significant rain due to persistent moist westerlies on the southern flank of the blocking high.

An unusually strong ridge of high pressure across Queensland, extending up to Cape York, has kept the monsoon trough north of the continent. This pattern is forecast to change as a deep tropical depression forms in the Gulf of Carpentaria over the coming days and moves south into northern Queensland. Unfortunately, the stubborn ridge of high pressure over central Queensland is likely to block the rain-bearing low from moving much further south over drought-stricken parts of inland Queensland and NSW.




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Coping with heat waves: 5 essential reads


While parts of the country have sweltered, the far southwest of Australia has experienced cooler and wetter than average conditions this month. Cape Leeuwin, Australia’s most southwesterly point, set a 123-year daily rainfall record for January, recording a massive 57mm of rainfall.


Bureau of Meteorology

In the short term, there is no indication that the blocking high will break down or move eastward. Forecasters on both sides of the Tasman expect the pattern to continue until February at least.




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The Conversation


Steve Turton, Adjunct Professor of Environmental Geography, CQUniversity Australia

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Sydney storms could be making the Queensland fires worse


Claire Yeo, Australian Bureau of Meteorology

A strong low-pressure system has meant severe thunderstorm and hail warnings are in effect for much of the New South Wales South Coast. At the same time, very dry conditions, strong winds and high temperatures are fuelling dozens of bushfires across Queensland.

The two events are actually influencing each other. As the low-pressure system moves over the Greater Sydney area, a connected wind change is pushing warm air (and stronger winds) to Queensland, worsening the fire conditions.




Read more:
Drought, wind and heat: when fire seasons start earlier and last longer


These lows over NSW are the kind we might see a couple of times a year – they’re not just regular weather systems, but neither are they massively out of the ordinary.

However, when combined with the current record-breaking heat in Queensland, the extra wind is creating exceptionally dangerous fire conditions. Queensland’s emergency services minister, Craig Crawford, has warned Queenslanders:

We are expecting a firestorm. We are expecting it to be so severe that it won’t even be safe on the beach […] The only thing to do is to go now.

Conditions in Queensland

At least 80 bushfires were burning in Queensland on Wednesday, with more than a dozen fire warnings issued to communities near the Deepwater blaze. Queensland Police Deputy Commissioner Bob Gee said that “people will burn to death” unless they evacuate the area.

These fires have come during a record-breaking heatwave. On Tuesday Cooktown recorded 43.9℃, beating the previous November high set 70 years ago by more than two degrees. Cairns has broken its November heatwave record by five whole degrees.

Grasslands and forests are very dry after very little rain over the past two years. Adding to these conditions are strong winds, which make the fires hotter, faster and harder to predict. This is where the storm conditions in NSW come in: they are affecting air movements across both states.

NSW low is driving winds over Queensland

A large low-pressure system, currently over the Hunter Valley area, is causing the NSW storms. As it moves, it’s pushing a mass of warm air ahead of it, bringing both higher temperatures and stronger winds across the Queensland border.

Once the low-pressure system moves across the Hunter area to the Tasman Sea east of Sydney, it will drag what we call a “wind change” across Queensland. This will increase wind speeds through Queensland and temperatures, making the fire situation even worse.

This is why emergency services are keeping watch for “fire tornado” conditions. When very hot air from large fires rises rapidly into a turbulent atmosphere, it can create fire storms – thunderstorms containing lightning or burning embers. Strong wind changes can also mean fire tornadoes form, sucking up burning material. Both of these events spread fires quickly and unpredictably.




Read more:
Turn and burn: the strange world of fire tornadoes


What does this mean for the drought

Unfortunately, it’s not likely the heavy rains over NSW will have a long-term effect on the drought gripping much of the state. While very heavy rains have fallen over 24 hours, the drought conditions have persisted for years.




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The wet weather may bring some temporary relief, but NSW will need much more rain over a longer period to truly alleviate the drought.

In the meantime, the Bureau of Meteorology will be monitoring the Queensland situation closely. You can check weather warnings for your area on the bureau’s website.The Conversation

Claire Yeo, Supervising Meteorologist, Australian Bureau of Meteorology

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Australia moves to El Niño alert and the drought is likely to continue


Skie Tobin, Australian Bureau of Meteorology; Catherine Ganter, Australian Bureau of Meteorology, and Robyn Duell, Australian Bureau of Meteorology

The chances of an El Niño developing late in 2018 have increased and this week the Bureau moved to El Niño ALERT. This means that model outlooks and observations indicate there is approximately a 70% chance that El Niño will develop in the coming months. Current patterns in the Pacific are similar to the early stages of past El Niño, with warm water shifting east towards South America.

We’re also seeing indications a positive Indian Ocean Dipole (IOD) has likely started, in which warmer waters near Africa drag moisture away from Australia. El Niño and positive IOD events typically mean below-average spring rainfall in central and southern Australia, and a drier start to the wet season in Queensland and the Northern Territory.




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The development of either would favour continued dry weather, and increase the likelihood that widespread drought relief will be delayed until 2019. Higher than average temperatures, heatwaves, and more severe bushfire weather are also more likely during El Niño and positive IOD events.

A dry year so far

September 2018 was a very dry month, adding to low rainfall seen across many parts of Australia so far this year. September 2018 was not only the driest September in 119 years of record for Australia, but it was also the second-driest for any month of the year (behind only April 1902).

Rainfall for the year to date has been exceptionally low over the mainland southeast, with much of the region experiencing totals in the lowest 10% of records for January–September. Many locations in eastern New South Wales, eastern Victoria, and southeast Queensland have received about 400 mm less rainfall than they usually would have by this time of the year.

Rainfall deciles for January to September 2018.
Bureau of Meterology

Much of southern Australia has experienced a persistent rainfall decline spanning several decades, which is adding to drought stress by drying the landscape.

Southwest Western Australia has experienced significantly lower cool season (April to October) rainfall since the mid-1970s, compared to observations since 1900, while for the southeast the drop has been more recent, emerging in the mid-1990s. These rainfall declines have been linked to circulation changes in the southern hemisphere influenced by the increase in greenhouse gases.

These rainfall changes have also been accompanied by much larger reductions in streamflow, particularly in the southwest of Australia where high flows have become much less frequent.

April to October rainfall anomalies (mm) for southwestern (left) and southeastern (right) Australia, showing the decline in totals with respect to the 1961 to 1990 average. The main feature of the decline is significantly fewer wet years, meaning recovery from the dry years is patchy.
Bureau of Meteorology

And it’s also been unusually warm

Low rainfall has also been accompanied by very high daytime temperatures so far this year. Of course, Australian temperatures are warming in line with global trends, but in individual years variations which are likely to be largely natural (such as droughts) may add to or subtract from the broader trends.




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Historically, droughts have often brought hot conditions, and this has been borne out in 2018. Maximum temperatures for January to September were the warmest on record for the Murray–Darling Basin and New South Wales, with neighbouring regions also much warmer than average.

These extremely warm days, combined with extremely low rainfall, have caused an intense drying of the Australian landscape in 2018, resulting in an early start to the bushfire season in New South Wales and Victoria, where damaging fire were observed as early as late winter.

So how might the year end?

Like all Australians, the Bureau hopes farmers and those suffering through drought get the rainfall they need, but unfortunately, the outlook indicates dry conditions are likely to continue for some time.

Large parts of southern and eastern Australia are likely to see a drier than average end to the year, though odds favouring drier than average conditions tend to moderate as we head towards summer. Most of the country is likely to see a dry October, though local heavy falls can occur against a backdrop of broadly suppressed rainfall.

Chance of exceeding median rainfall between October to December 2018.
Bureau of Meteorology

While some parts of New South Wales and southeastern Queensland have received very welcome rainfall in the first days of October, rainfall has been below average over much of over eastern Australia for so long (since early 2017) that this rainfall event hasn’t been enough to break the drought.




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Recent Australian droughts may be the worst in 800 years


Looking at temperature, outlooks show a very high chance of warmer than average days and nights through to the end of 2018. Considering the year so far has already been very warm, this means 2018 has the potential to rank as another significant warm year. Seven of Australia’s ten warmest years have occurred since 2005, with just one cooler than average year in the last decade (2011), highlighting how warmer than average temperatures now dominate Australia’s climate.The Conversation

Change of exceeding median maximum temperature between October to December 2018.
Bureau of Meteorology

Skie Tobin, Climatologist, Australian Bureau of Meteorology; Catherine Ganter, Senior Climatologist, Australian Bureau of Meteorology, and Robyn Duell, Senior Climatologist, Australian Bureau of Meteorology

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Spring is coming, and there’s little drought relief in sight


Jonathan Pollock, Australian Bureau of Meteorology; Catherine Ganter, Australian Bureau of Meteorology, and David Jones, Australian Bureau of Meteorology

So far, 2018 has been very warm and exceptionally dry over large parts of mainland Australia. The Bureau of Meteorology’s climate outlook for spring, released today, shows that significant widespread relief is unlikely.

The chance of a spring El Niño, along with other climate drivers, is likely to mean below-average rainfall for large parts of the country in the coming months.

A dry winter for most of Australia

Winter rainfall has been below average over most of Australia’s eastern mainland. Large parts of New South Wales are on track to have winter rainfall in the lowest 10% of records. This has compounded drought conditions in the east after mixed rainfall last year and a dry start to 2018 for much of the country.

But it’s not just the lack of rainfall that has made the impact of drought severe. Another factor was the warmer than average daytime temperatures.




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Warmest January-August on record for some

The 2017-18 summer average temperature was Australia’s second-warmest in 108 years of records, while autumn was Australia’s fourth-warmest on record. Winter 2018 is likely to be among the five warmest winters on record in terms of maximum temperatures.

Many of the above-average daytime temperatures have been focused over the country’s southeast. In fact, South Australia, New South Wales and Victoria are all on track for their warmest maximum temperatures for the January to August period.

The below-average rainfall combined with above-average maximum temperatures resulted in a rapid and intense drying of the landscape. This has led to unusually severe fire weather conditions in July and August – conditions more typically seen at the end of spring than the end of winter.




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Drought, wind and heat: when fire seasons start earlier and last longer


In contrast, low rainfall, cloud-free skies and dry soils mean it has been colder than usual overnight across most of the country during winter.

Climate conditions favour low rainfall

Will spring see a break in the warmer days and below average rainfall? Probably not. Both the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD), can be major influences on Australia’s seasonal rainfall and temperature patterns.

During winter, both ENSO and the IOD were neutral, meaning that neither of them provided a large influence on winter’s weather (so we can’t blame them this time).




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However, most international climate models have been forecasting a spring El Niño since June. Sea surface temperatures in the central Pacific have been gradually warming since autumn and are rising towards El Niño thresholds. At the beginning of June the Bureau went on El Niño watch, which indicates a roughly 50% chance of El Niño forming in 2018 – double the usual likelihood. El Niño during spring typically means below-average rainfall across eastern and northern Australia.

Three out of five international models are forecasting that a positive Indian Ocean Dipole event is also possible this spring. A positive IOD during spring typically means below-average rainfall in central and southern Australia. When El Niño and a positive IOD coincide, their drying influences can be exacerbated.

So, what’s the outlook for spring?

With a reasonable chance of both El Niño developing and a positive Indian Ocean Dipole, the outlook for spring shows below-average rainfall is likely over much of the southeast and parts of the northeast and southwest. The rest of the country has a neutral outlook, showing no strong push towards a wetter or drier than average three months.

Inland areas are typically dry at this time of year, so the neutral outlook in the arid interior typically implies that low rainfall is likely. No part of the country favours above-average rainfall in the spring outlook.

Spring days are likely to be warmer than average across Australia, with the highest chances (greater than 80%) over northern and western Australia. Most of the country is likely to have warmer than average nights this spring, except for areas around the Great Australian Bight which have roughly equal chances of warmer or cooler than average minimum temperatures.

What does this mean for the drought and bushfires?

Like the rest of the country, the Bureau is hoping that farmers in drought-affected areas get the rainfall they need soon. But this outlook isn’t the news many want to hear.

Last weekend’s rainfall over northeastern New South Wales and southeastern Queensland was welcomed by most, but unfortunately it was well short of what was required for a recovery from the longer-term rainfall deficits. Many locations on the east coast are well below their average year-to-date rainfall totals.

Rainfall deficiencies for the first seven months of 2018 in areas of western NSW, northwest Victoria and eastern South Australia widely show rainfall totals in the lowest 5% of the 118 years of record. It would take many months of above-average rainfall to return to average levels.




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The above average temperatures in 2018 so far, combined with below average rainfall and dry vegetation, mean a higher likelihood of fire activity in parts of southern Australia. The warm and dry outlook for spring means the drought in parts of the country’s east is likely to continue.


Learn how climate outlooks are made.The Conversation

Jonathan Pollock, Climatologist, Australian Bureau of Meteorology; Catherine Ganter, Senior Climatologist, Australian Bureau of Meteorology, and David Jones, Climate Scientist, Australian Bureau of Meteorology

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Drought, wind and heat: when fire seasons start earlier and last longer


Owen Price, University of Wollongong

The New South Wales Rural Fire Service declared the earliest total fire bans in its history this week. The entire state was declared to be in drought on the same day.

The combination of winter drought and hot, dry weather has made dangerous fires increasingly likely.




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Already this week two fires on the south coast have escaped containment lines and destroyed houses. The weather during these fires was 6℃ warmer than the August average, dry and extremely windy. The wind speed peaked at 104 kilometres an hour in Bega and 85km/h in Nowra, two towns close to where fires broke out.

Under these conditions, bushfires will spread quickly, produce large numbers of embers and are hard to stop.

Our fire seasons now start earlier and last longer. This means we’re increasingly likely to see repeats of historically large fires threatening residential areas.

Fire seasons are longer

Current dry conditions are reflected in the maps of live fuel moisture produced by Dr Rachael Nolan of Western Sydney University.


Nolan R.H., Boer M.M., de Dios V.R., Caccamo G., Bradstock R.A. (2016), Large-scale, dynamic transformations in fuel moisture drive wildfire activity across southeastern Australia. Geophysical Research Letters 43, 4229-4238.

This method tracks the weekly moisture content of the forests in southern Australia, as observed by NASA’s MODIS satellite. The latest map shows a patchy distribution of dry areas and a drying trend over recent weeks.

It looks like NSW’s fire season has already started, and it’s likely to be bad. Last year’s fire season also extended well into autumn, with serious bushfires burning in mid-April.

Fire agencies usually enjoy a six-month break from bushfires between April and September, but this year they had only three months’ respite.

This reflects evidence of a trend toward more extreme fire weather over the past 30 years, and lengthening fire seasons.

This problem is being keenly felt in western United States, where fire agencies have warned that the fire season now lasts all year round. Not only that, there is clear evidence climate change is increasing fire activity in the United States; the record for the largest fire in California history has been broken two years in a row.

Alarming precedents

The most damaging fire season for NSW in the past 30 years was in October 2013 when the Linksview fire destroyed 200 houses in the Blue Mountains.

The build-up to that season was eerily similar to this year, with a winter drought and bushfires in September, but the moisture maps show that the forests are drier now than at the same time in 2013, and we have already seen serious bushfires in August.




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Future bushfires will be worse: we need to adapt now


As we move into September and October, the weather will warm, which means any remaining moisture in the ground and plants will evaporate even faster than at present, and fires will be more intense and spread faster. The only thing that will reduce the risk is soaking rain of at least 100mm.

Whether or not that will occur in the next two months is almost impossible to predict. At the moment it seems unlikely. The Bureau of Meteorology’s latest seasonal forecast, issued on August 16, considers it likely that dry conditions will persist for the next three months.

The heightened risk of bushfire this season should be a wake-up call for residents in bushfire-prone areas. Most people in really risky areas such as the Blue Mountains are well prepared, but many people who are a little more removed from the forests are not aware of the risk.




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Where to take refuge in your home during a bushfire


For example, many residents of Wollongong probably don’t know this October is the 50th anniversary of the great 1968 fires that swept down the Illawarra Escarpment into the suburbs of Figtree, Bulli, Austinmer and others.

The footprint of the 1968 Illawarra fires, which burned through residential areas.

If the same footprint of fire were to occur again, some 5,000 houses would be affected. The present indicators suggest a repeat of this event is more likely than at any time for decades.

Residents need to prepare a bushfire survival plan, which includes a decision on whether to stay and defend or to leave as soon as they learn about a nearby bushfire.




Read more:
Our deadly bushfire gamble: risk your life or bet your house


Current research at University of Wollongong suggests that the biggest influence on the risk of house loss during a bushfire is the actions that the residents themselves take. This includes ensuring that natural and man-made fuels are kept to a minimum in the garden, especially close to the house, and also defending the house from spot-fires caused by embers.

The Rural Fire Service has a wealth of advice for preparing for bushfires on its website.

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The Conversation

We’re look at a torrid upcoming fire season, dependent on the vagaries of the Australian climate. Either way, now is the time for people to brace themselves and get prepared.

Owen Price, Senior Research Fellow, Centre for Environmental Risk Management of Bushfires, University of Wollongong

This article was originally published on The Conversation. Read the original article.

To help drought-affected farmers, we need to support them in good times as well as bad



File 20180808 191041 xb0wtk.jpg?ixlib=rb 1.1
Farmers need help to plan for droughts, not just to respond to them when things get desperate.
Stephenallen75/Shutterstock.com

Jacki Schirmer, University of Canberra; Dominic Peel, University of Canberra; Ivan Charles Hanigan, University of Sydney, and Kimberly Brown, University of Canberra

With the New South Wales government announcing that drought is now affecting the entire state, the federal government’s crisis assistance payments have been described by some as too little, too late. The National Farmers Federation has renewed its calls for a national drought policy and drought experts have expressed concern about reliance on emergency handouts.

With droughts predicted to grow in frequency and severity in the future, we need to support farmers and their communities to adapt to these changes.

To best support the well-being of farmers and farming communities, we need to support them not just when they are in the middle of a drought, but also when the rain comes and the dust has settled. An emergency response is important, but on its own is not enough – our farming communities deserve more. It needs to be accompanied by long-term coordinated support, delivered through the whole drought cycle, that helps farmers prepare for drought, cope with drought when it is happening, and recover rapidly afterwards.

Prolonged droughts harm the health and well-being of people in farming communities, although research also shows that not everyone is affected to the same extent, and some not at all. This means we need to learn from past experience in choosing what actions represent the best and most effective investments.




Read more:
Farmers experiencing drought-related stress need targeted support


Providing farmers with emergency assistance when drought is at its worst helps to alleviate the most acute hardship. But multiple inquiries and research studies (see here, here and here) have concluded that this approach is not enough.

To truly support the well-being of farming communities facing the threat of drought, we need to invest more in actions that support their preparedness and resilience before drought hits, rather than waiting until conditions are at their worst before offering help.

The hydro-illogical cycle

Doing this requires breaking the “hydro-illogical cycle”, in which a severe drought triggers short-term concern and assistance, followed by a return to apathy and complacency once the rains return. When drought drops off the public and media radar, communities are often left with little or no support to invest in preparing for the next inevitable drought.

The hydro-illogical cycle.
US National Drought Mitigation Center, Author provided

Farmers need proactive, long-term access to drought preparedness schemes well in advance, before the effects of drought begin to bite. Farmers who use programs such as the farm management deposits scheme, which allows them to put aside surplus income in good years and draw on it in difficult ones, have higher well-being during droughts than those who access emergency assistance provided during drought.

Our research has also identified some other ways to protect farmers’ well-being during challenging times. These include investing in forward planning for drought, supporting farmers to invest in “drought-proofing” measures suitable to their farm, and creating networks through which farmers can share their knowledge about what works to cope best with the financial, psychological and social challenges they face.

These things are not a “fix” for drought; a drought will always have significant impacts. But they can help reduce the severity of impacts, and the time taken to recover. However, to really be effective, these actions need to be invested in between droughts, in addition to investing in emergency support during drought.

We can learn a lot from the actions that farmers are already taking. Thousands of farmers have spent years investing in drought resilience, for example by changing pasture types and water management practices, and by changing how they plan for and manage periods of low rainfall.

This investment often goes unsupported and unrecognised, and has to be done among the ever-present pressures of challenging market conditions, low profit margins, rising costs, the need to repay debts incurred in the last drought or flood, and the myriad daily pressures of farming. We need to better reward farmers who make these investments, and to offer incentives for continued investment in this type of action between droughts.

Regenerative farming

One investment being made by many farmers across Australia is the adoption of regenerative farming, in which the entire farming system is re-oriented with a goal of better using natural ecosystem processes to support production, and of better matching production to land capacity through different climatic conditions.

Early research findings suggest that engaging in regenerative farming can improve drought resilience. But shifting to use of this approach to farming takes a lot of time and investment; before asking farmers to make fundamental changes to the way they farm, we need more research that critically examines when, where and how different farming systems can help safeguard against drought.




Read more:
The lessons we need to learn to deal with the ‘creeping disaster’ of drought


As well as helping farmers invest in actions to increase resilience to drought, we also need to consider the best ways to support those who are suffering severe psychological and financial stress. For many farmers, supporting them to cope with drought and stay in farming is the best decision. But for others, the best decision can be to leave farming altogether.

The decision to leave farming is understandably one of the most challenging times in a farmer’s life, and often happens when their well-being is low and they are experiencing psychological distress. This means that the quality of help they receive during this time can make a big difference in how well they cope. Services such as the Rural Financial Counselling Service have a vital role to play at all times (before, during and after drought) in giving advice to farmers weighing up the agonising decision to stay or leave.

If you want to help farmers, keep supporting relief funds – they provide essential help during the worst of drought. But also tell your local politician that you support investment in long-term programs that help farmers improve their resilience to the next drought, and the one after that, and that recognise and reward the investments farmers are already making in doing this.

The ConversationIf we truly have our farmers’ well-being at heart, we should be taking drought action in wet years as well as dry, and in good times as well as bad.

Jacki Schirmer, Associate Professor, University of Canberra; Dominic Peel, PhD Candidate in Public Health, University of Canberra; Ivan Charles Hanigan, Data Scientist (Epidemiology), University of Sydney, and Kimberly Brown, PhD Researcher, University of Canberra

This article was originally published on The Conversation. Read the original article.

Here’s how a complex low-pressure system sent temperatures plummeting



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The complex low weather system currently swirling over south-eastern Australia.
Bureau of Meteorology

Adam Morgan, Australian Bureau of Meteorology

New South Wales, Victoria, Tasmania and South Australia are currently affected by a massive complex low pressure system, dropping temperatures and bringing rain, hail, wind and snow.

While complex low pressure systems like this come along every year or so, some Australians may be feeling whiplash after a particularly warm autumn.

Complex lows

Typically, as Victoria and Tasmania head into winter we see cold fronts that move from west to east, generating rain and thunderstorms. This weather system started off like that, but developed into a complex low that will stay with us for the rest of the week.

It’s the kind of weather system you see on average once every year or two. What is a little unusual is to see such a deep pool of cold Antarctic air so early in May. Canberra, for example, is forecast to have a maximum of 9℃ on Friday – which would be its coldest day in the first half of May since 1970.




Read more:
Cold weather is a bigger killer than extreme heat – here’s why


In weather-speak, “complex” describes a weather system with an intricate structure. Starting as a cold front across Victoria and Tasmania, this complex low now has multiple low-pressure centres at the surface, and is interacting with a broad low-pressure system in the upper levels of the atmosphere. These upper and low-level weather systems reinforce each other.

The other factor contributing to the complexity is the warmer waters of the Tasman Sea. The East Australian Current brings warmer waters down the east coast, raising ocean surface temperatures in the Tasman Sea relative to the neighbouring Bass Strait and Southern Ocean. When these low pressure systems develop over the western Tasman Sea, that warm water provides a lot more energy through evaporation.

When all the elements align, with a cold front and its associated cold air mass moving over warm water, beneath an upper-level low in the same place providing reinforcement, a deep and complex low-pressure system can develop.

Difficult to predict

The Bureau of Meteorology usually has several days’ indication that a system like this may form, but development of multiple low-pressure centres at the surface makes it tricky to predict exactly where local impacts will strike.

These small-scale low-pressure centres influence exactly where the heaviest rain or strongest winds will be, as do features of the landscape like mountain ranges.

While we can make broad predictions of what may be on the way, it’s not until we get closer to the event that we can really start to be more specific about rainfall totals, wind speeds, and so on.

The Bureau gets minute-to-minute readings from our Automatic Weather Stations, but we have the ability increase the frequency of some of our measurements (for example, at the moment we have increased the frequency of weather balloon releases at Hobart airport), to get additional information about the atmosphere.

This system will move fairly slowly over the next couple of days, and different elements will impact different parts of Australia.

We’ve got cold air, wind and showers over Victoria and southern New South Wales at the moment, but there are parts of the east coast that are still quite warm today. Tasmania is starting to see windy conditions in Hobart and rain developing, and potentially heavy rain through the east of the state over the next couple of days.

Once the cold air moves further north into NSW we’ll expect snow at lower levels as far north as the Central Tablelands, and then as we move into the weekend the low pressure system will move out into the Tasman Sea.

We’ll then start to see swell increase, as the ocean responds to the weather system. Heavy swell and hazardous surf conditions could push well north along the NSW coast and potentially into southern Queensland by early next week.

Weather warnings

Currently, severe weather warnings for wind have been issued across parts of South Australia, Victoria, New South Wales and Tasmania. Heavy rain warnings and flood watches are in place in Victoria, and flood watches and warnings are current in Tasmania as well.

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Other specific warnings provide important information for those on the land – the Bureau has alerted sheep graziers, for example, to the impacts of cold, wet and windy conditions on exposed livestock.

While these warnings are all fairly standard for this kind of weather system, always follow the advice of emergency services. We’re the weather experts, but they’re certainly the experts on preparing for hazardous weather!




Read more:
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The ConversationWe’d also advise everyone to keep up with the forecasts and warnings on the Bureau of Meteorology over the next few days.

Adam Morgan, Senior Meteorologist, Australian Bureau of Meteorology

This article was originally published on The Conversation. Read the original article.

Lessons not learned: Darwin’s paying the price after Cyclone Marcus


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Fallen trees and power lines are two of the main hazards that could have been reduced with better planning for cyclones.
Geoff Whalan/Flickr, CC BY-NC-ND

Akhilesh Surjan, Charles Darwin University; Deepika Mathur, Charles Darwin University; Jonatan A Lassa, Charles Darwin University, and Supriya Mathew, Charles Darwin University

Darwin was directly in the path of Cyclone Marcus and suffered severe impacts from wind gusts up to 130km/hour on Saturday, March 17. Northern Territory authorities made no declaration of emergency, but the Insurance Council of Australia declared it a “catastrophe” for the Greater Darwin region. Marcus is considered the city’s second-worst cyclone since Tracy, which devastated Darwin on Christmas Eve 1974.

The good news is that no deaths have been reported. But had it been a category 4 or 5 cyclone, instead of category 2, how would the city have fared?

The post-Marcus chaos in Greater Darwin is not just “a real wake-up call”, but a typical case of lessons yet to be learned. For example, large shallow-rooted trees planted after Cyclone Tracy and overhead power lines brought down in the cyclone were both hazards that could have been avoided. Darwin is now engaged in a long, difficult and costly clean-up.

Fallen trees posed one of the biggest hazards during and after the cyclone.

Cyclones are to be expected

Indigenous knowledge as well as the Bureau of Meteorology’s historical records confirm that tropical cyclones are not new to Northern Australia. According to the BOM:

There are on average 7.7 days per season when a cyclone exists in the Northern Region.

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So was there complacency among some residents, as emergency services warned? Did infrastructure providers underestimate the threat? In hot and humid weather, over one-third of Darwin’s population went without power for several days and safe-to-drink tap water for 48 hours. Communication networks were patchy for days.

What was the reluctance in seeking immediate support from other states despite banks and insurers considering this a catastrophe? Was it due to Commonwealth disregard for the Top End in general?

How well has Darwin coped?

There have been at least two opposing views on the impact of the cyclone. The first is a more optimistic one, largely because no one got killed or seriously injured. Community members spontaneously helped one another in the immediate aftermath.

On this view, although preparedness might have varied, people in general were prepared. Power outages for a few days were a “first world problem”. Most households were ready, for example, to use camping gas cookers.

Volunteers visited and helped vulnerable groups such as aged and sick people. Emergency responders, defence staff and infrastructure restoration teams are working tirelessly to return the city to normalcy.

On the other hand, Marcus uprooted thousands of trees across Greater Darwin, mostly African mahoganies, which were planted for revegetation after Tracy.

Large shallow-rooted trees proved to be a poor choice for revegetating Darwin after Cyclone Tracy.
Priyanka Surjan, Author provided

Around 25,800 of about 60,000 properties across Greater Darwin were cut off from power. Even after a week many are still living in darkness. Power outages had cascading effects: traffic signals weren’t working for days at many places and food was left to rot in the heat.

Water was cut off in places. For about 48 hours people were urged to boil tap water before drinking, cooking or brushing teeth. The Health Department issued a warning about melioidosis, a life-threatening disease spread by contact with soil, mud and surface water.

Fallen trees blocked many roads and caused mild to severe damage to residential, commercial and public premises. Outdoor areas were cordoned off for safety.

Educational institutions were closed for at least a day. People who didn’t own a car or were unable to drive were disadvantaged for almost three days until public transport was running again.

At several locations, tree branches are still hanging dangerously over roads, pavements, parks and roofs. Anywhere in the city or suburbs, you see major and minor roads, parks and beachfronts dotted with uprooted trees and fallen branches. The roadside piles of logs and green waste are likely to remain there for some time, as their removal is not an “emergency priority”.

What does a city do with so much waste?

Waste facilities are struggling to cope. The morning after the cyclone, vehicles queued for hours at the green waste facility. It is yet to be ascertained if arrangements can be made to manage the huge quantities of green waste.

Vehicles loaded with green waste queued for hours at the waste management facility.

United Nations Environment Program (UNEP) guidelines note that waste debris presents opportunities as “either a source of income or as a reconstruction material, and [can] reduce burdens on natural resources that might otherwise be harvested for reconstruction”.

An evaluation of green waste would help understand its recovery value. Research suggests that disaster waste management can account for 5–10% of the total recovery costs, often exceeding that of health care and education.

In October 2004, a typhoon devastated Toyooka in Japan, producing 45,000 tonnes of waste – 1.5 years of the city’s usual waste production. The 2011 tsunami in Japan produced the equivalent of of 9 years’ worth of municipal solid waste in Iwate prefecture and 14 years’ worth in Miyagi prefecture.

What can Darwin learn from this?

Local government is considering removing mahogany trees, which were introduced after Tracy, because of their fast growth and the expansive shade their dense canopies provide.

Globally, environmental dimensions of disasters are less recognised compared with social and economic dimensions. However, the loss of dense trees and the valuable ecosystem services these offer calls for environmental recovery to be a priority as well.

A 2013 study reveals that large sums of taxpayers’ money is typically spent following disasters, whereas increasing pre-disaster investments can achieve cost savings and resilience.

As an example, the territory government is offering relief payments between A$250 and A$650 for households that were without power for 72 hours or more. The importance of putting power lines underground was recognised more than a decade ago but the work is incomplete due to lack of political will.

This is the time to ask questions such as: what will be the scale of devastation and cost and duration of recovery if a category 4 or 5 cyclone hits Darwin? The next cyclone after Marcus, Nora, was expected to be a category 4 storm but was downgraded to category 3 when it hit the western coast of Cape York on March 25.

Why not prioritise transformation of critical infrastructure, such as shifting all power lines underground? What role can cost-benefit analysis play to achieve resilience to category 4 or 5 cyclones and other natural disasters?

The ConversationMore broadly, how can we learn from the past? What are the new lessons we can take forward from Cyclone Marcus? And how do we inspire a city to work towards creating “Resilient Darwin’”?

Akhilesh Surjan, Associate Professor, Humanitarian, Emergency and Disaster Management Studies, Charles Darwin University; Deepika Mathur, Researcher in sustainable architecture, Charles Darwin University; Jonatan A Lassa, Senior Lecturer, Humanitarian Emergency and Disaster Management, Charles Darwin University, and Supriya Mathew, Postdoctoral researcher, Charles Darwin University

This article was originally published on The Conversation. Read the original article.