Halifax rapid fire development
Some interesting video came out of the Halifax fire last week of a news crew that was almost over run by the rapidly moving fire. Rapid fire development in wildland terms is usually called a “blow up” — when a fire goes from burning surface fuels and brush to suddenly involving all fuels. It is a phenomena similar to a flashover in structural firefighting when a critical combination of oxygen, heat, and fuel is reached and all surfaces suddenly ignite.
At the 8 second mark events occur quickly — you hear a comment about “getting dark,” then the camera has a partial white out (I assume from rapid fire growth), then the still photographer observes they have fire to their left. Press reports have stated, per Nova Scotia Forestry, the fire spread hit speeds of 36 meters per minute. That’s 107 chains per hour, 1.3 miles per hour, or 118′ per minute. In Connecticut spread rates over 30 chains per hour are considered Very High fire danger days, and over 40 are Extreme.
The above video is reminiscent to me of this video taken in the New Jersey pine barrens on 16 May 2007 when several New Jersey Forest Fire Service vehicles were involved in a near miss:
I have the above videos archived in case they disappear from YouTube, under videos.
Those videos help fill in the mental picture when you see photos like this one from Cape Cod, which has forests like the pine barrens of New Jersey:
Forest fire on Cape Cod, from Capecodfd.com
Or this AP photograph of an October, 1947 fire crossing Route 1 in Arundel, Maine:
October, 1947 Arundel, ME
When the fire is in the crown like this they can not be fought. In general the tactic is to leave these to burn and concentrate on handling the fire later when it has left the crown and is just burning the surface and brush, as these boys from Bates College are headed to do in ’47:
Boys from Bates headed to fight fire
At Bates, nearly 300 male students, volunteered for firefighting duty. A state disaster committee dispatched the volunteers to help fight the fires in towns like Bowdoinham, Kennebunk, Cornish and Richmond. Meanwhile, female students conducted watches on campus and at Thorncrag, raked leaves away from residence halls, and collected clothing donations for the Red Cross.
Clicking on the Bates photo will bring you to a page which recounts the tale. In case it disappears I’ve archived off a couple of the tales here.
Even the brush breakers of southeastern Massachusetts aren’t intended to attack these crown fires directly, but instead to allow them to rapidly access deep into the woods to control the fire while it’s still in the brush and not a crown fire.
Fire storms like those pictured above are not survivable to those caught in the open. In parts of the U.S. the “fire shelter,” an aluminized tent carried on your belt is common. Australians tend to use their fire apparatus as shelters, specially equipping them with blinds to keep out the radiant heat from the cab and misting systems to wet the outside of the truck. A flame front like that is also survivable in a properly prepared home, which it doesn’t look like the Halifax homes were, when the occupants are prepared after the flame front has passed to come out and extinguish spot fires around their property.
