FOCUS ON FIRE
IN THE FOREST
FUNCTION OF FIRE
A GRASP ON SMOKE
BEYOND THE BLAZES
By Cary Shimek
When wildfires erupted across western Montana in 2000, I stubbornly rode my bike to work through the haze. No stupid fires were going to take away my exercise or ruin my summer.
But while I was at work one day that August, a plume of dense smoke blew north from the burning Bitterroot Valley and settled like a shroud across Missoula. A Stage 2 Air Alert was declared, which meant particulates had risen to 150 micrograms per cubic meter of air. That didn’t mean much to me, but it was recommended that the elderly or people with asthma not exercise outside.
Since I was in reasonably good shape, I decided to brave the 6-mile ride back home. I pedaled through a white ghost world as I left the UM campus. Buildings across the street were hazy; you could stare at the dun-colored sun. The campfire smell was inescapable.
My mouth went dry instantly, and halfway home I was breathing sandpaper … and then knives. After reaching my doorstep, I could only take short, gasping breaths for the next half-hour.
The next day I drove.
Then it happened again in 2003 — fires, smoke, national forests closed, retardant bombers roaring overhead, burning forest homes, people trapped indoors during summer’s best weeks. At night we watched the Black Mountain fire glow just beyond city limits.
Intense fire seasons are no picnic in the American West, and Missoula has experienced two whoppers this decade. And UM forestry Professor Steve Running says we may need to get used to them.
Running is a leading expert on global climate change. He directs a lab that created software for two NASA environmental satellites that monitor the Earth’s health from space. They check the global temperature, vegetation, fires, snowpack and a host of other factors on a daily basis. Running also is helping write the 2007 report of the Intergovernmental Panel on Climate Change. The panel’s 2000 report states the Earth’s climate has demonstrably changed in recent decades, and some of those changes are attributable to human activities — especially emissions from our machines, factories and fires.
Running says there is irrefutable proof the world has warmed about two degrees Fahrenheit on average in the last 100 years. That may not sound like much to the layperson, but Running believes those two degrees are powering major climatic shifts that appear to be accelerated by pressures of human population and economic activity.
In the Northern Rockies those two degrees mean our winters are ending up to a month earlier than they did in 1950. Running says that way up north in Edmonton, Alberta, the budburst of the aspen is coming a month earlier. Such an early spring melts our mountain snowpack more quickly, which in turn extends our fire season for four more weeks in late spring and summer.
In addition, there seems to be less snowpack to melt. According to Science magazine, snowpack levels have declined 15 percent to 30 percent in the Northern Rockies and as much as 60 percent in the Cascade Mountains of Washington and Oregon.
Running’s group did a detailed study of Missoula’s climate during the past 50 years and found that the average temperature rise is more pronounced in the spring. He says the average March temperature was 32 degrees in 1950. In March 2000 it was 38 degrees.
And all of Running’s climate-change models point to continued warming in our region — perhaps as much as 4 to 14 degrees Fahrenheit on average over the next 100 years, depending on the rate of increase of greenhouse gases in the atmosphere.
If a 2-degree rise in the last 100 years gutted our snowpack and lengthened our springs, what would 4 degrees do? It might get hot. Burning hot. Summers like 2000 and 2003 — and 2005 turned out to be no picnic either — could become commonplace.
“Everything we believe shows that we already had our average fire season expand by approximately a month in the last 50 years,” Running says, “and we are fully imagining that it could expand another month in the next 50 years. Already our fire season in bad years seems to get rolling in mid-June instead of mid-July like it did in the old days.”
Running says snowpack is the one attribute of the Northern Rockies climate that has changed the most. “Midsummer temperatures are pretty much the same,” he says. “It’s not really getting hotter in the summer — except our nights are a bit warmer. But when you look at the whole rest of the year and at other aspects of climate, nothing seems really big yet except this springtime snowmelt.”
So what will the climate of the Northern Rockies be like in 50 years? Running suspects western Montana may become more like western Oregon, where there is more rain in the winter than snow. That’s too bad, because the nice thing about snow is that once it falls it stays for awhile and requires a lot of energy to melt it off. Whereas water can evaporate more quickly, leading to drier landscapes and earlier fire seasons.
Western Montana has been spared massive fire seasons the last two years because of wet Junes, but Running says that can’t always rescue us.
“Hot, windy days can actually evaporate a quarter-inch of water a day,” he says. “So a couple of inches of rain that we receive in June can easily be evaporated away with a couple of weeks of hot weather. And if the rains don’t keep coming, we get into trouble.”
So, are the hills around Missoula going to start looking like the sagebrush mountains of Nevada in the next 100 years? Running says the vote isn’t in yet. Because — from an ecosystem point of view — getting warmer in itself might not be too catastrophic if more moisture comes with it. And the higher temperatures of climate change will make select areas wetter.
“For western Montana, higher temperatures with more rain mean we kind of transition to a western Washington kind of climate,” he says. “It hardly ever snows in winter in Seattle, but there is lots of rain. So we could end up with a milder climate that actually grows more trees.”
But our climate also might get warmer and drier, which Running describes as “a dramatically more detrimental trajectory.” Then many of our tree species might slowly and progressively die off, and there will be more wildfires.
However, a wetter climate for the Northern Rockies also could spawn more extreme fires depending on the seasonality of the rain. More moisture could grow more vegetation — fire fuels — and if the moisture comes during mild winters and the summers stay bone dry, then that’s a recipe for extremely catastrophic fire years. Running assures me that Montana will get warmer in coming years, but the great unknown is whether more moisture will come with it.
“From what we see so far, it’s not getting wetter,” he says, “but it might be too soon to tell. Some models suggest we might get wetter in this region, but I’m not sure how accurate our algorithms are. And that is absolutely the pivotal question — a question that I’m furiously trying to build a data set to answer … for the whole world.”
Running says a warmer Montana could have some advantages. For instance, deer and elk winterkill should go down, crops could be planted earlier and forests might be more productive. But new problems may arise, such as disrupted animal hibernation patterns and increased insect disease trends in forests. And early springs lead to extremely low-flow conditions for streams in late summer, which increase water temperature, decrease dissolved oxygen and stress out fish. The state’s blue-ribbon trout streams might become less productive.
With less snowpack, skiing also will suffer in coming years. Running says it’s already happening, pointing to the closures of the Beef Trail ski area near Butte and the Marshall Mountain Ski Resort near Missoula in recent decades. Those resorts declined as snow became less dependable, and Running hints he would think twice before building any new ski hills in the region.
Fire always has been part of the natural ecology of the Northern Rockies, and the landscape will continue to burn periodically — whether we want it to or not. People have unnaturally suppressed fire for the past 100 years, and now climate change makes this tinderbox more likely to burn.
So are more intense wildfire seasons on the horizon? Increasingly smoky summers with more Stage 2 Air Alerts? Running says most scenarios point in that direction. We will get warmer, but the question remains whether moisture will come with the increase in temperature. Right now it appears we are getting warmer without additional moisture.
All this makes fire science and our understanding of forest ecosystems ever more critical. We need to understand what’s coming so we can react appropriately.
The stories in the following pages explore efforts by UM scientists to understand fire and its impacts on our environment, health and society. They examine the burning questions that will be faced by Montanans for generations to come.
For more information, e-mail Running at email@example.com.