Saturday, December 26, 2015

Lorne Bushfire perspective-

Visitors to the Otways are reminded of  just how bush fire risk develops in the SW Victoria. This limited info was published previously in the interests of education about the most common bushfire types in our area,  The info  below does not mean other wind patterns and risk will not occur.
-- Best to get out of the area and stay out of areas of bush when there is a risk of strong northerlies

1 NORTHERLY driven Phase ( Firefront moves in a arrow like form shown as WHITE or BROWN on the aerial photo below .... generally moving to the SSE being driven by northerly winds

eg The Ash Wednesday fires which started at Cudgee...NORTH is up the page

Fire origin is at top end .

and   Deans Marsh ( red area)(in summer of  1983 North is up the page with southern ocean around Lorne shown

shows how dangerous it is to be in the bush when strong northerly winds ( incl; especially NNW) occur .
This time the first phase is in RED and BROWN and second phase in YELLOW

-- Best to get out of the area and stay out of areas of bush when there is a risk of strong northerlies

2. SOUTH WEST driven Phase
 ( fire front moves to the ENE)(yellow on photo)
The historic fires also shows SECOND PHASE that is often common after the FIRST NORTHERLY phase  This can be the biggest and most unpredictable phase because a wide front on the east side of " the arrow" opens up,  with winds speed and direction often more variable.

 Visitors must keep clear of the area to the NE and E of such fires as well as the southerly areas;

The Christmas day fires 2015 show this typical scenario with two phases  , as do the 1939 fires  ( see Northwest  -South east alignment  of Grampians and the final fire edges to the east .

YEODENE  fire also shows the initial phase only ( March 1998 ) Yeodene
Even though we are talking about the most common and long term trend,  it does not mean other wind patterns cannot occur .

For guidance only . Keep radio  on emergency broadcasting stations if travelling in the area. Use Apps available for mobiles top get up top date map info.

Sometimes the normal SW wind change is not strong which was a great relief in March 1998

when a fire with a northerly driven wind threatened major parts of the Otways.  The wind change occurred much earlier than expected on the 12th March and the expected evacuation did not occur. note the spotting ahead of the fire .