29 August 2007

Fire bans in August? An overreaction?

The Country Fire Service has issued an unseasonal and hence surprising fire ban advice for tomorrow:


Issued at 5:05 pm on Wednesday, 29 August 2007

Thursday 30 August 2007 is forecast to be a day of extreme fire danger,
especially in bushland and forest areas, and the Country Fire Service has
imposed Total Fire Bans in the following districts:

West Coast
Eastern Eyre Peninsula
Lower Eyre Peninsula
Mount Lofty Ranges

For more information on restrictions, phone the CFS Hotline on 1300 362 361 or
go to http://www.cfs.org.au

Yes, the Bureau of Meteorology state forecast does predict high winds and high temperatures:


Issued at 4:20 pm on Wednesday, 29 August 2007
For tonight and Thursday.

Please do not use this forecast after 6 am Thursday.

A Gale Warning has been issued for all South Australian coasts.

Fine Wednesday evening. Warm to hot and dry at first on Thursday with northerly
winds increasing to strong to gale force with locally raised dust. A cooler,
strong and squally southwesterly change developing west of Ceduna during the
morning, then extending to remaining district during the afternoon and evening.
Isolated showers developing across the agricultural areas behind the change.
Winds moderating in the west Thursday evening. Fire Danger rising Very High to
Extreme in forest and bushland during Thursday.
But, repeat but, has anyone from the CFS or the BOM looked out the window and at the Adelaide Hills (in the Mount Lofty Ranges fire ban district), which are, as usual at this time of year, covered in green? The ABC News online story misrepresents the situation by including a photo of the CFS in action on dry grass.

Adelaide (today's max 20.5 deg) is considerably warmer than the Mount Lofty Ranges (today's max at Mt Lofty 14.2). Does the prospect of 28 in Adelaide, followed by a cool change and possible showers, justify a total fire ban?

In my experience fire bans in the Mt Lofty ranges are imposed when the Adelaide est max is 35 or more. Does this mean that 28 is the new 35? In my experience it's quite feasible to walk in the parks near Adelaide, eg Cleland and Morialta, on most days when the estimated max is in the high 20s, and in the morning or late afternoon of many days when the temperature exceeds 30.

The "weather bureau" spokesman quoted by the ABC acknowledges that this is a first:

Allan Beattie, from the weather bureau in Adelaide, says the conditions will be hazardous until a forecast change later in the day.

"One thing we probably haven't seen in all this before is a fire ban for the Mount Lofty Ranges but we have one for tomorrow," he said."The highest temperature recorded in Adelaide is 29 [for August], we're going for 28 tomorrow so we're within one degree of our extremes."

Hardly an unequivocal endorsement of the CFS action, methinks. Of course I hope that no fires start (or are started), but imposing a fire ban looks unnecessary.

Update 30 August 2130 CST

Well today certainly turned out to be hot, even hotter than forecast. Adelaide's maximum reached 30.4 degrees, an all time August record. It was windy (with strong gusts) and warm, but I've not heard any reports of fires, which is good especially given that the fire ban and the accompanying publicity must have tempted some local pyromaniacs to emerge from hibernation.

For a detailed analysis of today's weather see the estimable hillsrain website.

My comments yesterday weren't meant to play down the potential damage to agriculture, but to question the need for a fire ban in the Mt Lofty Ranges on a day when a cool change and rain were forecast. The 2135/9.35pm temperature is now 17.1 in Adelaide and 10.7 at Mt Lofty, and tomorrow's forecast is for a much cooler day, so we can be grateful that this spasm of heat was so short. We do need more rain though.

Further update 30 August 2200

It is now raining outside. I hope it continues, despite the unpromising forecast, for some time.

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