Warrandyte Chat

Hi All,

The past few days have brought a flurry of queries regarding the Fire Districts. There are two districts relevant to bushfire which have different boundaries.

Total Fire Ban District – for legislation governing lighting of fires & use of equipment to prevent ignitions of fire.

Yarra Area / Region 13 is in CENTRAL

2. Fire Danger Ratings District – for prediction of likely bushfire behaviour, impact potential & advice on action.

The FDR district is based on the weather districts of the Bureau of Meteorology. The advantage of this is being smaller districts they are more localised, however there still may be a large variance in the conditions across the district. People on the borders of districts should consider both districts.

Yarra Area / Region 13 is in CENTRAL

The maps provide information about 2 different things although of course the declaration of a Total Fire Ban is dependant on weather conditions.

Your planning for bushfire should be considering the Fire Danger Rating as well as if it is a TFB day. The triggers people use will vary – some use all TFB days as their trigger, others have different plans for different levels of FDR.

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The Bureau of Meteorology also has the specific Fire Danger Index in chart format which lists the individual weather stations. – this has caused some confusion.

The design of the chart lists the individual weather stations first then the district as a footer underneath. ( If you read it incorrectly with the district as a header it will read as though Coldstream & Dunns Hill ( Ferny Creek ) is in Nth Central.- wrong )

The most relevant weather stations in Central District to Yarra Area / Region 13. are

Dunns Hill ( Ferny Creek )

Coldstream

These 2 weather stations are recording the weather conditions at these 2 sites so it is very localised information.

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Hope this helps in your planning & in understanding predictions & negotiating the new ratings.

Regards Helen

Helen Wositzky

Community Fireguard Coordinator.

CFA Yarra Area

18-22 Lakeview Drive

Lilydale, Vic. 3140

Hi to all FireGuard members.

Hope you all had a good Christmas & New Year.

As you will be aware we are heading into a few hot days, keep aware of the Fire Danger Ratings and particularly local conditions over the weekend & into early next week. I urge everyone to make sure their preparations are done and to activate their Bushfire Survival Plans.

Community messaging systems.

There are a number of community developed messaging and alert systems that are currently in operation using text messages to mobile phones, emails or web based messages. ( apart from your localised CFG group phone trees ). A few of these I am aware of are 19Fire and Firelinx, some CFG groups and individual CFG members have subscribed to receive messages through these systems.

It has come to our attention that some text and email messages received by people through some of these community developed systems have got CFG in the messaging. I have received some enquiries regarding this and for some people this is causing confusion regarding the origin & source of the messages. To clarify this please note the following:

· Community developed & organised communication systems allow individuals to subscribe if they choose to receive information through these systems.

· The messages are community generated messages from within the community and shared to those who have subscribed.

· These systems are not part of the official Community FireGuard program, although CFG group members are of course free to subscribe to them if they wish.

· These messages are not official CFA messages, they are not authorised messages from CFA and messages are not sent from the CFG program or authorised by the CFG program.

· CFA or the CFG program has no input regarding the content of these messages, the frequency of messages sent, or the timing of when a message is sent.

· All Bushfire Advice, Watch & Act or Emergency Warning messages that are produced by the CFA are authorised and distributed to the official channels such as the CFA website, Radio and TV.

Gaining as much information through as many sources as possible regarding bushfires is an important part of your bushfire plans and community generated messages may be a valuable tool in gathering information. We are not discouraging people from subscribing to any community generated messaging systems they feel may be of benefit, however it is essential to understand the information provided is coming from other community members not CFA.

Hope everyone is good & stay safe over the coming weeks.

Regards Helen

Helen Wositzky

Community Fireguard Coordinator.

CFA Yarra Area

Article from David Packham

The fire weather estimates for Thursday 19 Nov 2009 are looking a little concerning.

The Forest Fire Danger Index (FFDI) for the North West of the State is in the 60 – 90 range, the Grass Fire Danger Index (GFDI) is in the 40 – 60 range.
Both of these indices are such as to cause serious fire behaviour.
The predicted rate of spread would be around 3 kph in the forests with heavy fuels. The predicted flame heights are around 40 metres with spotting up to 3km. The Byram Fire Intensity for the forests about 50 Megawatts per metre some twenty times greater than firefighting capability (2.5 Megawatts per metre being the limit to direct attack).

The very dry areas around Bendigo and Shepparton are somewhat similar but the grass greenness is keeping the GFDI at a manageable level, in other words good firefighting in the grasslands should be successful but not so in the heavy forests and I might add along the neglected roadsides.

The central areas, for example Tullamarine, look serious for forests with FFDI just reaching the 50 mark, the GFDI with an estimated curing of around 50% ( half the grass stalks are still green) is sufficiently low to be initially manageable with good fire fighting and very early response. I would not be surprised if the curing did not rise rapidly during the day as happened during the Lara Fires in 1969.

The West, Northeast and Gippsland both look difficult except for the grasslands in the West where the grass is still apparently all green .

The serious concern for me is the synoptic situation which like Ash Wednesday 1983 is proving difficult for the forecasters. They have gone for a “more pessimistic forecast” thus the analysis above could be worse than what actually occurs.

The problem is our old enemy the Southwest wind change. If it is a prolonged and nasty one like Ash Wednesday the results could be very difficult. The problem being the response times of the fuels which remain dry just after the wind change even though the FFDI and the GFDI show them becoming much more moist. That is because we are using the models beyond their capability.

I would suggest that we watch carefully the developments in the systems over the next few days whilst preparing for a possible big fire event on Thursday (due to the heavy grass and forest fuels and the ignored roadsides). On Thursday the major threat would come in the late afternoon and the timing of the wind change will be critical.

This early in the season normally I would discount any real fire problems but the dryness continues and we could be in for an unpleasant surprise.

With a little luck the forecasts may change as the weather systems develop and the day may pass us with a whimper rather than a shout.

Once again I hope the above analysis turns out to be wrong.

David Packham