We all know that wildland fires are larger than they used to be. Almost every summer recently there are fires that exceed 100,000 acres. Before 1990 this was not common.
I analyzed some fire occurrence statistics obtained from the National Interagency Fire Center and the National Incident Information Center. The numbers for 2007 are through November 4, 2007. Usually when fire occurrence statistics are displayed you will see total acres and the number of fires by year. But when I computed the average size of fires for each decade, the 1970s through 2007, a trend is painfully obvious. During those four decades the average size of fires increased by 400%, while the average number of fires each year decreased by 44%. (Click on the graphs to make them larger.)
But why are fires larger? Some of the factors that could cause such an increase in the average size are:
Fire suppression for the last 100 years is catching up with us. Preventing naturally occurring fires to routinely reduce the fuel loads increases the amount of fuel, and the continuity of it, available when a fire starts. Fires burn more intensely and with more resistance to control.
Climate change. There is no doubt that temperatures in the last few decades have been higher that they were before this period. We can debate how this may have affected wildland fires. Many areas have had extended droughts, causing die back of brush and shrubs. Trees are stressed, making them more susceptible to insects and other pests. Do these higher temperatures have a direct effect on fire behavior on an hour by hour basis?
The Safety and Health Working Team, part of the National Wildfire Coordinating Group, on January 15 released a “Safety Gram” listing the wildland fire related fatalities in 2007.
“Nine fatalities occurred in 2007 when employees were performing wildland fire management activities. This is a substantial decrease from the 24 fatalities that were reported in 2006. Also noteworthy is the absence of any entrapment or burnover related fatalities.
Aviation – 1: Fatality occurred when helicopter was performing logistical support.
Driving – 3: Fatalities occurred when firefighters were returning from a prescribed fire (1) and training (2).
Hazard Tree/Snag – 1: Fatality occurred when a tree fell on a firefighter during chain saw training.
Heart Attacks – 2: Fatalities occurred following the Work Capacity Test (pack test) and firefighting.
Other – 2: Fatalities occurred when a dozer rolled over while constructing fire line (1) and by electrocution (1).”
The U.S. Fish and Wildlife Service in South Dakota has been experimenting with a tractor-towed machine that creates black lines which can be put in prior to a prescribed fire. Black lines, a relatively narrow strip of burned vegetation along the perimeter of a planned prescribed fire project, can make the ignition and holding of the main burn go much more quickly and also reduce the chance of a slop-over.
The equipment is made by Firebreak Equipment, a firm in South Africa. Their web site does not play well with Firefox–it’s better with Internet Explorer. More photos are on their web album.
The device uses propane burners in a metal enclosure to burn the ground fuel, while water nozzles on the sides create a wet line to keep the fire from spreading. This toy tool looks like it would be fun to play with.
I have seen coal seam fires in Alaska that were started by lightning, but until today I had never heard of a “coal refuse fire”. Apparently they are pretty common in southeast Ohio where the Wayne National Forest has been dealing with this mostly underground, one-acre “Coal Dale” fire since October 29. Now they are saying it is out.
“Using heavy equipment, D.J. Group, Inc. from Beverly spread the burning coal debris out onto a previously stripped mined area where it was extinguished. Once the material cooled, the entire area was graded to its original condition. This spring the area will be reseeded and planted with trees native to the area.”
Here is a link to the InciWeb info, but it has not been updated since November 20. (photo by US Forest Service)