This week, Cody Beedlow woke up in a familiar place 8,000 feet up on Oregon's largest glacier, nestled in a tent covered with fresh-fallen snow and surrounded by scientific instruments.

BEND — This week, Cody Beedlow woke up in a familiar place 8,000 feet up on Oregon's largest glacier, nestled in a tent covered with fresh-fallen snow and surrounded by scientific instruments.

Beedlow, a 28-year-old native of Corvallis and a graduate student at Oregon State University, has been making the 8- to 9-mile trek up to Collier Glacier, nestled between North Sister and South Sister, nearly every month for the last two years as part of an extended project to find out more about why the glacier is shrinking.

There's no question Collier Glacier has been getting smaller over the last 100 years or so. Pictures taken by the Mazamas mountaineering club in the 1920s show the glacier more than a mile farther down the slope than it extends today. Pictures taken since then have produced what Beedlow describes as a "time-lapse photography" record of the glacier retreating toward higher altitude.

Getting an answer about why the glacier is shrinking is more complicated. Is it melting at lower altitudes as a result of overly warm summers? Or is because of inadequate snowfall in winter, reducing the ice accumulation that builds up at higher altitudes and creeps downhill over time? And how do temperature, wind, humidity, solar radiation and other variables factor in to what's happening in both summer and winter?

The answers could help Beedlow develop a formula that can predict the advance and retreat of glaciers, and the glacial runoff that feeds streams and irrigation systems.

Beedlow's project is a continuation of work began by Peter Clark, a professor of geosciences at OSU and Beedlow's adviser. Along with a prior graduate student, Clark made several trips to Collier Glacier between 1989 and 1994, but his self-admitted lack of mountaineering skills and the unavailability of modern instruments limited what he could do. In the years since then, little research has been conducted on the glacier.

"It kind of fizzled because of logistical issues; he never had any good winter measurements up there," Beedlow said. "He wasn't able to get up there he's not a skier, so he tried dogsleds, cross-country skis, snowshoes, and really was not very successful at trying to obtain winter balance measurements."

Clark said Beedlow is far better prepared for the challenges of working in an alpine environment than he was 20 years ago.

"The dogsled attempt might have worked if we'd had decent snow, but it was a very poor snow year, so the conditions were not good for sledding. We made two miles in one day," Clark said. "We did get in once on snowshoes, but then a fierce storm came in, and we had to hightail it out of there. Bottom line is, you need to be an experienced mountaineer such as Cody is."

Along with four assistants, Beedlow spent three days and three nights on the glacier last weekend, measuring snow depths and densities, mapping the boundaries of the ice, and downloading a month's worth of weather data from a weather station he's installed on the mountain.

Beedlow's weather station, built in his garage and carried in piece by piece in backpacks, would have been unimaginable when Clark was working on the glacier.

Powered by a lithium polymer battery about the size of a Hershey bar a type originally put to use in radio-controlled cars and planes, but increasingly seen in laptop computers the weather station can run for about four months, recording reams of weather data on flash drives. Snow measurements are conducted in cruder fashion, with marked PVC pipes that Beedlow has driven into the ice.

Although Beedlow won't be able to draw any conclusions until later this fall, a cool spring and summer means there's a good chance the glacier will add mass this year. Even before the surprise snowstorm Monday morning, there was a lot more snow still on the glacier through the summer this year than last summer.

"We got really good storms in April and May, June was very cold, almost winter/springlike, and that allowed snow to stick on the surface of the glacier a bit longer," he said.

One year in which the glacier adds mass will not change the longer-term trend, Beedlow said, noting that Clark's five years of monitoring showed just one year where the glacier added mass.

Clark said it's extremely satisfying to have a student capable to taking up where he left off nearly 20 years ago.

"Absolutely. It's especially great to see him thrive on this because it allows him to combine his mountaineering interests with his scientific interests a great match for him," Clark said.

Beedlow said he'd love for a future OSU student to carry on his research once he graduates, but acknowledged it's a challenging project to do right. He's carried a 60- to 65-pound backpack for every trip up the mountain, climbing the glacier with ropes and crampons and keeping an eye open for hidden crevasses.

Even in the summer, work can be treacherous. Monday, he and his team woke up to the sound of an avalanche thundering down a nearby slope and decided they'd best get off the mountain.

"That's the nature of this kind of research you're kind of at the mercy of the mountain. I get turned back a lot," he said. "There's been a lot of trips I've tried to make out there and the mountain just says no, whether it's scary avalanche conditions or too much snow or monsoon-like rain. It's really quite humbling; the mountain really has a way to put you in your place."