Expedition Seeks to Answer How Warming Will Affect Snow

Matthew Sturm thought he had died and gone to heaven the other day when he gazed across the Arctic landscape, bathed in brilliant light from the midday sun. It was such a lovely day, he recalled later, that the temperature almost got up to freezing.

He's hoping it will stay that way for a while because Sturm is leading an extraordinary expedition across Alaska's forbidding Brooks Range and into the Arctic plain, a trip of nearly 500 miles, all by snowmobile. If all goes according to plan, Sturm and his five associates — including an 8th grade science teacher from Morganton, N.C. — will pull into Barrow, the northernmost town in the United States, by the end of April.

But as a veteran of that part of the globe, Sturm knows that just about anything can happen along the way. Blizzards can blow up out of nowhere, plunging temperatures down to dangerous levels and filling the air with blinding ice crystals, even in April.

"A sunny day at minus 10 with no wind is just glorious," he said shortly before leaving Nome on March 21.

That's easy for a snow scientist to say. For the rest of us, almost any day along the unknown passages through the mountains and to the north would be just plain "nasty," he admits.

Elusive Northern Snow

Sturm, a geophysicist at the U.S. Army's Cold Regions Research and Engineering Laboratory at Fort Wainwright, Alaska, is making this difficult journey for one reason. Scientists really don't know much about the snow that blankets the far north for most of the year. They aren't even sure where it comes from, since there is no obvious source of moisture in a region that qualifies as a desert in every way but temperature.

Worse yet, they know the weather is getting warmer in the Arctic, but they don't know how that will affect the snow.

And that leaves an enormous gap in our understanding of the future of global climate patterns.

"As climate changes, snow is likely to change," he says, but nobody knows exactly how. So scientists usually treat snow like they did clouds in the early days of concern over global warming — they just leave it out of the models. They know that will come back to haunt them eventually, because the Arctic snow cover has a tremendous impact on weather patterns thousands of miles away.

Snow, for example, reflects solar heat back into space, thus impacting what's called the earth's "radiation budget," a major driver in global climate patterns.

So the National Science Foundation came up with the funds for Sturm and his colleagues to make their journey across Alaska, collecting snow samples and conducting experiments at more than 100 sites. That's one reason the trip will take at least 35 days. People who race snow machines (locals call them "iron doggers") could do it in a few days, he says.

April Cheuvront, a science teacher from Table Rock Middle School in North Carolina, joined the expedition and is filing nearly daily reports on her web site (for her students back home. The other members of the team are Glen Liston, a research scientist at Colorado State University, Ken Tape, a graduate student at the University of Alaska, Fairbanks, Jon Holmgren, of the Army's cold regions lab, and Eric Pyne, an oil field worker who is making his fourth trip with Sturm.

There are a few native villages along the way where the researchers will meet with students and tell them about their work. The first few days of the journey have been relatively easy, Sturm said in an interview from the village of Buckland via a satellite phone, because they've been able to follow the "highways." That's bush country talk for trails.

Once they reach Ambler, on the south flank of the Brooks Range, they'll have to make their own trails.

Grainy or Crusty?

The goal is to sample snow along the entire route, because snow north of the Brooks Range is quite different from that found to the south. Below the range, the snow is large grained, providing a "tremendous insulator" for vegetation, thus allowing wildlife to continue their foraging by pushing their noses through the snow.

But north of the range, the snow is almost constantly battered by fierce winds, resulting in tiny crystals that blanket the land with sheets of ice.

"These two types of snow cover are almost opposites," Sturm says.

One question Sturm hopes to answer is basic. Where did the snow come from? South of the range, the snow almost certainly comes from low-pressure systems moving up from the Aleutian Islands and the Gulf of Alaska. But the Brooks Range acts as a "tremendous climate barrier," keeping those storm systems trapped to the south, Sturm says.

One theory holds that the northern snow actually originates in Eurasia. The researchers will collect samples to be analyzed for traces of industrial pollution, and various chemicals, in hopes of backtracking the course of the snow.

They will also measure snow depths, density and layering to determine regional trends in the snow properties.

At stake here are very fundamental scientific issues. No one knows how global climate changes will alter the snow. No one knows if there will be more snow, or less. No one knows if the changes — whatever they may be — will ameliorate or accelerate global warming.

That's a hole in our understanding that's big enough to drive a snowmobile through. Sturm and his team hope to come up with enough data to help plug that hole.

At least it's more exciting than one of his previous expeditions. He spent 40 days one spring, north of the Arctic Circle, "watching the snow melt."

Lee Dye’s column appears weekly on ABCNEWS.com. A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.

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