Natural Catastrophe Modelling

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Australia needs a national crisis plan, and not just for bushfires

By Andrew Gissing, Risk Frontiers and Michael Eburn, Australian National University
Published in The Conversation, 13th December 2019

Bushfires aren’t the only catastrophic emergency Australia is likely to see. AAP Image/Mick Tsikas

Calls are growing for a national bushfire plan, including from former prime minister Malcolm Turnbull, who says they are an issue of national security and the federal government must provide hands-on leadership.

It’s true that more people are living in high-risk bushfire areas, emergency services are stretched and the climate is rapidly changing. Future crises are inevitable. We must consider the prospect of a monstrous bushfire season, the likes of which we’ve never seen.

But bushfires aren’t the only catastrophe Australia must prepare for. If we are to create a national crisis plan, we must go much further than bushfire planning.

Not just bushfires

In the decade since Victoria’s Black Saturday fires, we have improved fire predictions, night-time aerial firefighting, construction codes and emergency warnings. All of these have no doubt saved many lives.

There are calls for more resources to fight fires, as part of a coordinated national plan. But few people have proposed an all-encompassing vision of such a plan.

For a start, it should not be confined solely to bushfires. Far more people die during heatwaves and residential housefires. Tropical cyclones, floods and hail each cost our economy more.

Any plan must provide a strategic vision across these various facets for at least the next ten to 20 years.

A national firefighting force?

Calls for a national firefighting force to supplement existing state resources are fundamentally short-sighted. A national force – quite apart from the level of duplication it would create – would spend much of its time idle.

Even during severe fires, such as those now raging, there would be limits to its usefulness. At a certain point, the size and energy of the fires means no amount of firefighting technology will extinguish them all.

Research conducted by Risk Frontiers, the Australian National University and Macquarie University through the Bushfire and Natural Hazards Cooperative Research Centre, has focused on better planning and preparedness for catastrophic events.

This research concludes it is unrealistic to resource the emergency management sector for rare but truly catastrophic events. It is wildly expensive to remain 100% prepared for the worst-case scenario.

Despite the smoke blanketing Sydney, we need to think beyond bushfires. AAP Image/Neil Bennett

Instead of simply scaling up existing arrangements, we need to think differently.

Bush firefighting could be improved by innovation and research. Future investments must focus on rapidly detecting and extinguishing ignitions before they spread out of control.

Everyone is responsible

States and territories are traditionally responsible for emergency management in Australia. But almost by definition, a catastrophic disaster exceeds one’s capacity to cope – inevitably drawing on nationwide resources.

This means preparing for catastrophic disasters is everyone’s responsibility.

Existing plans allow for assistance across state borders, and between state and federal governments. But there is no national emergency legislation defining the Commonwealth’s role or assigning responsibility for responding to a truly national disaster.

The Australian Defence Force has a well-defined support role in natural disasters but should not be relied on due to its global commitments. Expanding its role to firefighting would distract it from its primary role of defending Australia.

However, resource-sharing between states could benefit from more investment in programs that enable emergency services to work better together.

Bushfire haze at the SCG in Sydney during a cricket match. AAP Image/Craig Golding

International help in massive emergencies also needs better planning, particularly around timing and integration with local agencies.

Non-government organisations, businesses and communities already make valuable contributions, but could play a more central role. We could look to the US, which successfully uses a whole-of-community approach.

This might mean emergency services help community organisations provide aid or carry out rescues, rather than do it themselves. These organisations are also best placed to make sure vulnerable members of the community are cared for.

The most important task is to reduce the risk in the first place. The vast majority of disaster-related spending goes on recovery rather than risk reduction. Calls from the Productivity Commission and the Australian Prudential Regulation Authority (APRA) for more disaster mitigation funding have been largely ignored.

The federal government’s recent National Disaster Risk Reduction Framework highlights the need to identify highest-priority disaster risks and mitigation opportunities.

This would see priority investments in flood mitigation and strengthening of buildings against cyclones in northern Australia. (This will also help address insurance affordability.)

Land-use planning needs to be improved to reduce the chance that future developments are exposed to unreasonable risks.

Infrastructure must be constructed to the highest standards and, following a disaster, destroyed buildings should be rebuilt away from dangerous areas.

Finally, communities have the most critical role. We must understand our local risk and be ready to look after ourselves and each other. Governments at all levels must facilitate this spirit of self-reliance. Local leadership is crucial to any crisis plan and communities need to be involved in its construction.

Eastern Australia’s bushfire crisis has triggered emotional arguments for throwing resources at the problem. But planning must be careful and evidenced-based, taking into account the changing face of natural disasters.

Read more

https://theconversation.com/12-simple-ways-you-can-reduce-bushfire-risk-to-older-homes-122712

https://theconversation.com/what-has-australia-learned-from-black-saturday-111245

https://theconversation.com/extreme-weather-makes-homelessness-even-worse-heres-how-we-can-help-82758

https://theconversation.com/friday-essay-living-with-fire-and-facing-our-fears-128093

 

November 2019: Sunshine Coast Hailstorm

by Salomé Hussein, Foster Langbein, Jacob Evans

On the afternoon of November 17th, 2019, the Bureau of Meteorology (BoM) issued a warning that Queensland would experience severe wind and giant hail. Multiple news sources reported cricket-ball sized hail in the greater Sunshine Coast region. Accompanying videos and images from social media, both during and after the event, often depicted the damage wrought by the deluge, with shattered car windscreens being a common sight. The Insurance Council of Australia (ICA) declared the Sunshine Coast storm a catastrophe two days later. The majority of claims lodged thus far have been for motor vehicle. The current estimated loss value is $115M as reported by the ICA. For comparison, the current bushfires (declared a catastrophe from November 8th) have an estimated loss of $165M.

Risk Frontiers implemented the same approach for this storm as for the December 20th, 2018 Sydney hail catastrophe[1]. To determine storm footprints and estimate damage extents, the Maximum Estimated Size of Hail (MESH) algorithm ((originally due to Witt et al. (1998) )[2] was applied to radar volumes from the Australian Open Radar Dataset (AORD). The Marburg and Mt. Stapylton radars near Brisbane were chosen, over the time period from 10:00AM to 4:00PM AEST. Location of radars and the MESH results are shown in Figure 1. Image processing is applied to the cumulative MESH grid over the time period to extract the boundaries of the storm (using a threshold of 20mm, the criterion for a severe hail event in the BoM Severe Storms Archive). An ellipse is fit to that contour to compare against HailAUS, our detailed catastrophe loss model for hail, in order to estimate losses for the event.

Figure 1. Cumulative MESH grid over the event period, with radar locations indicated. The maximum hail size, using the PyHAIL package and the Marburg radar, was 7.7cm.
Figure 2. Multiple spatially separate footprints, outlined in red, may be extracted from a single event. The largest and most severe is normally selected for simplicity. Ellipses overlain in transparent blue indicate a qualitative goodness of fit to the extracted storm contours. Postcode boundaries are indicated in grey. The December 20th, 2018 storm had two distinct cells, one in the Berowra/Hornsby area, the other near Liverpool, which was consistent with SES callouts and news reports following the event.

Using the 20mm threshold ellipse fit and a range of hail sizes around the absolute maximum size detected of 7.7cm gives estimated damages of $150M +/- $40M using the HailAUS7.1 damage module against the PERILS 2018 Hail Industry Exposure Database. It is worth noting that the apparent storm footprint obtained from radar may not be equivalent to the ultimate damage footprint. The hail trajectories as they fall from the stormcell will be influenced by ambient wind. There is also a discrepancy in the location of max hail size relative to the ellipse centroid (the ellipse is fitted to an outer contour, but the 3D shape of that geometry is asymmetric along the ellipse axis).

Following the above event, on November 26th, the North Shore and Northern Beaches of Sydney experienced severe winds and pea-sized hail over a relatively short time window. The hail from this event is not expected to have generated much damage given the size. However, fallen trees from the wind disrupted transport and damaged structures and vehicles. The event caused multiple power outages in those areas, affecting 52,000 addresses at the peak of the storm with 13,000 addresses still without power 4 days later. The loss from this single event would be relatively small, but similar events could accrue substantial costs over the course of one season (hail is most frequent in the summer months).

[1]  Risk Frontiers, March 2019 Newsletter

[2] An Enhanced Hail Detection Algorithm for the WSR-88D, Witt et al, 1998