WATCHOUTS & RED FLAG WARNINGS
Most fire crews is Australia already have a list of watch-outs close-to-hand when they are on a job. Through training they are familiaried with these and, hopefully, will be vigilant when a potentially dangerous situation develops.
Through the Bushfire Cooperative Research Centre’s HighFire Risk Project, we now have a vastly improved knowledge of the key drivers of dangerous fire behaviour in rugged landscapes. Very little of this new understanding was available when past watch-out lists were developed.
Most of the wildfire suppression industry in southeast Australia is founded on the McArthur meter system and its derivatives. What these are based on is a weather continuum, and a fire danger index that reflects that weather. As the weather – temperature, relative humidity, wind speed and drought – changes, so too does the fire behaviour, in a predictable manner.
We now know that most of the catastrophic fire events in the high country of southeast Australia have been driven by discrete events that are not part of the weather continuum. They therefore are not picked-up by the fire danger indices.
We also suspect that these same events have been involved in many fire crew fatalities both here and overseas.
Thunderstorms and wind changes are well-known examples of discrete weather events, for which fire crews are already well briefed. They are included here to make a more complete list.
It is thus essential that we work to make fire crews vigilant for these events and able to immediately react in the prescribed safe manner. It is important that no-one delays the required actions because they were unfamiliar with the exotic concepts of channelling, foehn winds or whatever else nature throws at us.
In the US they have a system of Red Flag Warnings: “A Red Flag Warning is a forecast warning issued by the United States National Weather Service to inform area firefighting and land management agencies that conditions are ideal for wildland fire ignition and propagation.” We need to go beyond that system, as the events now known to be dangerous in southeast Australia are often not detected in the Australian weather observation network. We need to rely as much of the observational skill of fire service staff, and on a diverse range of internet resources.
To further aid this cause, a series of watch-outs are also provided to give some guidance as to what things might look like. Further detail is available through the HighFire Risk web site.
Just to repeat for clarity:
- Watch-outs are based on observing things happening.
- Red Flags warnings are signals that incident management objectives need to be reviewed, if not altered, on the basis of threats to safety.
This list is intended to AUGMENT, not replace, any existing lists of watch-outs or safety alerts.
Acknowledgements
The material here is based on a wide range of recent research into the drivers of catastrophic fire behaviour in and around the high country of southeast Australia, including Tasmania.
Key research streams include:
- BushfireCRC research into meteorological processes, under Graham Mills of the Centre for Australian Weather and Climate Research.
- BushfireCRC research into the drivers of risk in the High Country (HighFire Risk Project) by Jason Sharples and Rod Weber at UNSW@ADFA and Rick McRae at ACT Emergency Services Agency.
- Research into unusual combustion processes by John Dold at Manchester University and Rod Weber.
- Research into eruptive fire behaviour by Domingos Xavier Viegas of the Centre for Studies on Forest Fires and University of Coimbra.
- Research into violent pyro-convection in USA, Canada, Israel, Australia and elsewhere, coordinated by Mike Fromm of the US Navy Research Laboratory.
There have also been successful collaborations between these streams.
This material arises from work carried out by the HighFire Risk Project.
Material prepared by R. McRae September 2009.