Montana trail managers and rangers travel long distances to measure remote snow sites

Snow courses, which are spread throughout the Montana’s mountain ranges, are one tool the Natural Resources Conservation Service uses to measure snowpack and predict stream flows.

Many of the state’s snow-course sites have been replaced by automated SNOTEL sites, which transmit data without the need of people on the ground, but in certain areas, especially wilderness areas, snow surveys are still done by hand.

Ian Bardwell is the trails manager and natural resource specialist for the Lewis and Clark National Forest out of Choteau. For safety, he brings a volunteer, Jeremy Franks, along to help him.

The snow course is marked by orange metal posts and orange numbers posted on trees.

The numbers mark 10 snow survey stations. At each station, Bardwell sticks a probe into the snow and removes a core sample of snow. He weighs the tube with the snow inside, using a small scale that he can hang from a ski pole. Franks takes notes, and from the numbers Bardwell calls out, Franks can calculate the water content in the snow.

Those numbers are sent to the Montana NRCS office in Bozeman. Staff there calculates the average from the 10 measurement points and uses the data to create its monthly snowpack report.

While survey crews do measure snow depth, the more important piece of data is the snow water equivalent, said Lucas Zukiewicz, NRCS water supply specialist for Montana. That number represents how much water is being held in the snowpack and helps the NRCS make a water supply forecast, which predicts stream flows and the amount of water that will be available for irrigation.

Of Montana’s 90 snow-course sites, some are easier to reach than others. Snowmobiles are used to get surveyors to many sites. Helicopters are also used for some high-elevation, hard-to-reach sites. In wilderness areas, neither of those modes of transportation is an option. Instead, surveyors travel by ski, foot or horseback depending on conditions.

Three times a year, Kraig Lang, backcountry and snow ranger for the Lewis and Clark National Forest, travels 75 miles through the Bob Marshall Wilderness Area to do four snow surveys in the North Fork Sun River drainage.

The trip takes him about a week.

The four snow course sites Lang surveys have continuous records that date back to 1949.

Even SNOTEL sites have to be visited in person at least once per year to make sure they’re accurate.

“Part of locating one of these sites is you want to be able to get to them every month,” Zukiewicz said. “That snow course has to be able to be measured for a really long time for it to be meaningful.”