Flames leapt from pine trees and expensive rooftops beneath the red glow of a massive fire and a lowering cloud of smoke. Colorado's Waldo Canyon blaze drove nearly 30,000 people from vulnerable hillside homes in Colorado Springs. Two hundred sixty-five square miles burned in New Mexico's Gila National Forest. Even before the end of June, a good deal of the Intermountain West was blazing. Should we blame climate change? A century of fire suppression? Freak weather?
Possibly all of the above. First of all, the intermountain West has had freak weather. On June 26, the temperature in Colorado Springs reached an all-time high. Some people "are trying to argue this [unusally hot, dry weather] is an extreme," notes Lisa Graumlish, dean of the University of Washington's College of the Environment and an expert on climate change. But "extreme events are by their nature rare," and "we don't have the data" to say that this year's acute conditions reflect a changing climate. However, she says, we do know — and "this is really important" — that "spring has been coming earlier and earlier." This isn't conjecture. It "is a trend we can look at . . . through good observational data."
On top of the heat spike, less snow has been falling in the Rockies. Last year, Graumlich and her graduate students published a paper in Science explaining that such low snowpack in both the northern and southern Rockies hasn't been seen since the 1500s. What was happening then? No one knows, although Graumlish assumes it had something to do with Pacific Ocean currents. Now, climate change caused by human activity helps to drive the process.
The bottom line is that there's less snow and therefore less lingering moisture in the mountains than at any time in the past 500 years. As a result, "fuels are drying out a month ahead of time," Graumlich explains. Earlier drying means earlier fires. "We're having fires in June that we would normally have been having in August."
Graumlich and her team think this is the new normal. "It's almost like a step change," she says. In the late 1980s, we seem to have crossed "a threshold where we lost that [normal Rocky Mountain] snowpack. . . . This was a train wreck that we could see coming." And the pattern reinforces itself. "We're seeing the jet stream gradually move northward as the earth warms." Consequently, "winter storms that bring snow to the southern Rockies are less frequent. . . . That incremental slow movement of the jet stream north just results in less snow. It melts off earlier."
"The other climate-related trend," Graumlich says, "is the beetle-killed forest." If the weather warms up earlier, "for a number of the forest pests . . . life cycles are accelerated." That means more beetles and other pests killing more square miles of pines and other trees. With early springs and massive beetle kills, "you've got your fine fuels drying out," Graumlish explains. "You've got your big fuels dead." In other words, you have the tinder to start a fire and the big wood to keep it going.
A lodgepole pine forest that hasn't burned for 100 years has lived out its alloted span. It's time for the bugs and the fires. And in other forests, the fuel has built up more than nature — or native cultures — would have allowed. "These forests have not burned in decades," says David Peterson, who leads the Fire and Environmental Research Applications Team at the Forest Service's Pacific Wildland Fire Sciences Laboratory and also serves as a UW Affiliate Professor, Environmental and Forest Sciences. "Forests that would have experienced fires once every 10 to 30 years now haven't burned in 70 or 80 years."
What's sauce for the Southwest is sauce for the Northwest, too. Washington may not have as many beetle-killed trees as B.C. — although, Peterson says. the devastation in British Columbia "certainly has gotten everyone's attention," — but it does have a lot of dead and dying lodgepole pine forests just waiting to burn.
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