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Snow survey team’s data gets wide range of use

Janice Kurbjun
Summit Daily News
Aspen, CO Colorado
Janice Kurbjun/Summit DailyChris Pacheco, left, and Mike Gillespie with the Natural Resources Conservation Service in Denver, were up on Berthoud Pass last week conducting snow surveys. The data they collect help the state estimate snowpack and spring runoff levels.
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BERTHOUD PASS, Colo. – Mike Gillespie plunged a sampling tube into the ground, and as he hit the frozen soil, he paused and leaned toward the ground. Using tick marks on the tube’s side to measure the snow’s depth, he recited values to Chris Pacheco as they sampled from about a dozen spots approximately 25 feet apart in a 250-foot long course in late December at Berthoud Pass.

Gillespie then pulled the tube from the ground with a snow core sample inside. It’s weighed to measure the snow-water content, which helps determine spring runoff forecasts. Back at the office, the data points are averaged to account for variations in terrain, wind impact, trees and more.

Gillespie and Pacheco are the Denver-based snow survey supervisor and assistant supervisor with the Natural Resources Conservation Service. They have been doing snow surveys for 30 years, but the process – and its resulting data – has been of importance for more than a century in the West.



It all started in Lake Tahoe area, Pacheco said, where Dr. James Church realized that part of a solution to the ongoing water wars was to predict how the lake would rise each spring. In 1904, he established a snow course and began gathering data. Some of the first runoff forecasts were established in 1910 as text-based pamphlets that were mailed out to interested parties.

“The western United States relies on snowpack for about three-quarters of its water,” Pacheco said. “As demand for water increases, there’s more of a need to understand the content of the snowpack … It’s a vital part of living in the West.”




The concept caught on in Colorado in the 1930s, during the Dust Bowl era, Gillespie said. Since then, the information has been mostly useful to farmers and ranchers in the West so they can plan in mid-winter how they will operate in summer. However, with the evolution of data presentations (charts, graphs, maps) and distribution methods (primarily the Internet), user types have also changed.

As Gillespie and Pacheco began setting up their survey equipment on Thursday, two backcountry skiers called out from the nearby trees.

“Backcountry skiers are among the fastest growing users of the data,” Pacheco said, adding that avalanche forecasters also use the data to complement their own.

Municipalities and reservoir operators are also among those seeking information gleaned from the surveys, which includes snowpack depth and snow-water content. The information is further synthesized into broader streamflow forecasts.

So far this snow season, it’s good news for those filling reservoirs in the state and those looking forward to water-dependent summer recreation, Gillespie said.

According to SNOTEL information, the statewide snowpack is at 134 percent of average. In the Colorado River Basin, it’s at 145 percent of average, while the Arkansas River Basin is at 102 percent of average.

“The state is in excellent shape right now,” he said. “In the last several weeks, the snowpack conditions have dramatically turned around, especially in the southern parts of the state. … We need good snowfall for the next several months for us to come out above average for the season.”

“The northern part of the state has been above average almost since the get-go,” Pacheco added.

Each of the more than 200 monthly measurements will continue to help the Natural Resources Conservation Center update runoff forecasts. The season’s first bulletin is to be issued next week.