LOLO PASS — A beeping sound echoed through the Beacon Training Park at Lolo Pass on Wednesday as a group of sixth-graders from Sussex School used transceivers to locate beacons hidden under the snow in a practice avalanche search-and-rescue exercise.
Although it was pre-planned, the field trip came a week after an avalanche on Mount Jumbo in Missoula. That slide went only partway down Jumbo, and no one was injured. But it came on the five-year anniversary of a Jumbo avalanche that killed a woman.
The transceivers, or beacons, transmit signals that other beacons can search. In the case of an avalanche, search-and-rescue teams can use beacons to find buried skiers or outdoor winter recreationists who are wearing the devices.
“You can think of the magnetic fields like an apple split open,” said Elizabeth Fricke, the director of outdoor programs at the University of Montana and who volunteered to help with the field trip. “They’re coming out in these big orbs so I’m searching for something, it’s going to be bringing me around the magnetic field and then it’ll bring me into it.”
Fricke showed students how to use the transceivers to pick up a signal and then follow the directional lines on the receiver, known as flux lines, to locate the beacon. Once they located it, she instructed students to dig in a fan pattern to remove the snow in a way that made it easy to pull someone out.
After instructing the students, they gave it a try.
The students assigned themselves roles and went over a series of questions before embarking on their search.
“Did they have their beacon and was it turned on?” said Loris Tegeder.
“Does everyone have beacons on search?” said Maizy Miller.
“Is the scene safe?” the group said in unison.
Miller held one of the transceivers as two other girls came behind with probes. They followed the flux lines, and as they got closer, they began calling out numbers that stood for the number of meters from the buried beacon. As they got closer and the beeping got louder, they stuck the probes in the snow to find the beacon.
The beacon training park at Lolo Pass is one of five sites in western Montana, including Big Sky Brewing, Montana Snowbowl, Lost Trail ski area, and the Driftriders warming hut at Seeley Lake, where people can practice with beacons.
“For kids living in Montana and recreating outside, it’s really good to have some basic knowledge, and getting that as middle schoolers is even better,” said Betsy Craske, the fifth- and sixth-grade STEM teacher at Sussex who led the field trip.
“Whether it’s cross-country skiing or snowshoeing or skiing at the resort or backcountry skiing, it’s good knowledge for everyone to have,” Craske said.
Craske planned the field trip to expand on the class unit on snow and avalanche science.
“To have an avalanche, you need a slope that’s steep enough to slide, a trigger, so something triggering the avalanche, and then an unstable layer of snow,” Craske said.
Craske led another activity with the sixth-graders to assess the stability of the snowpack by digging snow pits and taking measurements.
The students spent nearly an hour digging a pit in over 6 feet of accumulated snow, where they leveled a wall and stuck popsicle sticks to mark different layers.
After marking each layer, students looked at snow crystals and measured the temperature gradient by taking the temperature of the top and bottom of each layer.
“If it’s more than 10 degrees Celsius per meter within that layer, that’s the temperature gradient, which means that the snow is becoming faceted, meaning more angular, so somewhat less stable,” Craske said. “If it’s less than 10 degrees Celsius per meter then it’s rounding and bonding and becoming more stable.”
Once the students are back in the classroom, Craske said they will crunch the numbers and calculate the stability.
Although snowpack, snow depth, surrounding terrain features, weather conditions and the snow layer temperature can be used to forecast avalanches, Craske said avalanches predictions aren’t always certain.
“We talked about risk-taking not only in backcountry skiing or traveling in avalanche terrain but also just what that looks like in their lives as middle schoolers,” Craske said.
Although some students might not use the lesson, she said it’s helpful for them to have a base knowledge and it’s another element of understanding the winter ecology of the environment they live in.
Other students, like Shelton Fricke, said the information will be helpful for when she goes backcountry skiing with her parents, although her mom who leads a class on avalanche safety, seems to know a thing or two.