Snow Packed

Melted, it cascades from the mountaintop to your faucet

Mark Williams spent much of Monday afternoon digging into chest-deep snow whose melt may one day fill a Boulder drinking glass.

Twenty miles to the east and more than a mile below, downtown temperatures climbed into the 70s, wilting petals off the Pearl Street Mall tulips.

Across roughly 550 acres of stunning alpine terrain just east of the Continental Divide, the University of Colorado geography professor, a field technician and eight student volunteers prodded and sampled the snow of Boulder's Silver Lake watershed below Niwot Ridge.

Niwot Ridge
Amid spectacular peaks and rock formations, Paul Abood, a University of Colorado geography graduate student, prepares to follow CU professor Mark Williams' tracks to the next snow pit Monday. Mark Leffingwell/Daily Camera

The watershed supplies 40 percent of the city's water. Much of it arrives as snow that piles up above the 11,500-foot timberline, in frozen dunes as deep as 30 feet.

The annual three-day effort adds data to a long-term snow monitoring project under way since 1997. The project is yielding new insights into the great frozen water-storage vaults of the Mountain West.

Williams, 54, looks the part of a mountain man, with a graying beard and the body of a former tight end. He spent a decade running a backcountry ski operation and then cutting trails in the Sierras before turning to academia in the 1980s.

"It got me interested in how the mountains work," he said earlier, as he pulled on the long steering levers of a 30-year-old Thiokol Spryte snow cat, packed with supplies and lurching up the mountain.

Williams runs the Long-Term Ecological Research program at CU's Institute of Arctic and Alpine Research, known as INSTAAR. The site is one of 26 where scientists from the Everglades to Antarctica observe humanity's influence on pristine habitats.

Snow chemistry analysis of samples during the annual effort has shed light on the effects of nitrogen deposition, a product of fossil-fuel combustion that acts like lawn fertilizer.

Mark Williams
Mark Williams uses a rubber mallet to drive a half-meter plastic tube into the edge of a snow pit to collect snow samples for chemical analysis as Paul Abood prepares gallon-size Ziploc bags to pack the samples out. Mark Leffingwell/Daily Camera

Each acre of the snowpack study area has been showered with about 10 pounds of nitrogen over the past decade, Williams said. The tundra's flora suffers, having evolved to grow cautiously and shut down if a midsummer blizzard strikes, he said.

Chemical analysis also plays into Williams' work in assessing where the water now pouring into Boulder's swollen streams comes from. That effort challenges the "Teflon basin" theory of mountain snowmelt, which says most snow slips straight to streams like an egg sliding off a frying pan.

Snow above the timberline is low on magnesium, calcium and other minerals that leach into groundwater exposed to rock. Yet chemical analysis shows mountain stream flow to be relatively heavy with such substances.

He found that about 65 percent of the rushing waters - once thought to be pulsing with fresh snowmelt - probably spent a year or more in high-mountain aquifers.

He pointed to fields of rubble at the base of a nearby slope. Such talus can be 20 to 30 feet deep, he said, and 50 percent porous.

"The gaps store a lot of water," he said, much like the alluvial fans where mountains meet the plains.

David Clow, a research hydrologist with the U.S. Geological Survey in Lakewood, said in an e-mail that some basins fit the Teflon basin model more than others, with none being completely non-stick.

"Our research in Rocky Mountain National Park indicates that at least a portion of the water in streams is at least a year old," he said, although most stream water there seems to be from snowmelt.

Williams stood above his second snow pit of the day, a refrigerator-sized hole west of

Neff Williams
Todd Neff, left, Daily Camera reporter, and CU professor Mark Williams walk toward Navajo Peak searching for a spot for Williams to dig a snow pit in the Green Lake 4 study area below Niwot Ridge. Mark Leffingwell/Daily Camera

Green Lake 4. He would stab its walls repeatedly with a 1,000-cubic-centimeter wedge and measure the slice's snow-water content on a scientific scale. He read the results to Paul Abood, a graduate student with a backpack full of Ziploc-bagged snow.

The project's data was also a key input to work by Williams and Tyler Erickson, who recently received his Ph.D. from CU. They were able to mathematically model the seemingly whimsical ways the wind piles up snow or strips it away above timberline. They found predictable patterns based on snowfall, wind patterns and topographical features.

"Everybody thought it was impossible to map an alpine basin, but this drift is here every year," Williams said, pointing to one of many mounds of snow in view.

Williams said he and others are working to extend their research to predict snow accumulation patterns and spring runoff throughout the Rocky Mountains and eventually mountain ranges around the world.

Carol Ellinghouse, Boulder's water resources manager, says she keeps tabs on such efforts, but tends to base Boulder's water decisions on more concrete data.

"We follow them to understand natural systems better, but in the end we have to follow what's happening on the ground because we have to have water flowing out of faucets," she said.