Alexandra Pope, staff writer
May 13, 2011 — The return of warm, dry weather means forest fire season is in full swing in many Canadian provinces. Human-caused fires are easily prevented, but sometimes nature has its own ideas.
Mike Wotton, a research scientist with Natural Resources Canada based in Sault Ste. Marie, is exploring the link between lightning and forest fires. He's working on models that could help fire agencies predict where lightning-sparked fires are likely to occur.
More reliable models could help prevent hundreds of destructive fires.
“Lightning leads to about half the fires that occur annually on average in Canada,” Wotton says. ”What we find is the fires that result from lightning lead to about 80 to 85 percent of the area burn so the vast majority of the area burn in Canada comes from lightning fires.”
Most people think of trees as lightning hazards, but for Wotton, the key to predicting forest fires lies not in the treetops, but on the ground.
Many lightning strikes do hit trees, he explains, but it's where the electrical current goes next that determines the likelihood of a fire.
Wotton's models use soil moisture as an indicator of the fire danger.
“Understanding whether a lightning strike is just going to run through wet soil and not lead to an ignition or run through soil that’s a little bit dryer and create this smouldering ignition is what we try to model,” he says.
“We have a ... Canadian forest fire weather index system that gets used across the country for making that determination.”
It's still impossible to predict the lightning strikes themselves, but people can do their part to mitigate the forest fire danger by heeding burn bans and other advisories. The Weather Network's Forest Fire Watch index is a good place to start.