Silverton, Colorado hosts the Silverton Avalanche School each winter. http://www.silvertonavalancheschool.com/ I came to take the level I course. This place gets lots of snow, and the village is surrounded by tall peaks in all directions. On a grey snowy day the village feels especially small and quiet.
As night fell I could get a hint, through breaks in the clouds and snow, of how close the mountains were.
The town is most active in the warmer seasons when the Durango & Silverton narrow gauge railroad is running. http://www.durangotrain.com/ But a few places are open all year. They provide good food, good company - plenty of indoor warmth.
On my first clear morning I could see that the surrounding mountains get sunlight a couple hours before the village.
By noon the sun had warmed things from the night's low of a 'balmy' -10F to +10F.
Our second day's field session was our first short tour into the backcountry near Red Mountain Pass. We would not travel far, but we would do plenty of snow and terrain analysis.
Our group was on skis (tele and randonee/AT) and climbing skins. Other groups had some members on snowshoes. For this short tour it really didn't matter what method you used to access the backcountry.
Our instructor was very thorough and deliberate in showing us what to look for when assessing the snowpack for signs of instability. (This level I course is just the start. Silverton also teaches level II, and Crested Butte hosts a level III course.)
After our short climb we could see another student group across the valley, digging pits and analyzing the snowpack.
Close up view.
Sometimes our instructor showed us simple and quick tests of near surface layers. Other tests required getting off your skis and digging a deeper pit to assess the types of snow layers, and their shear strengths.
As students, our eyes would wander to higher slopes...wishing we were skiing.
But we saw obvious signs of snowpack instability - skier triggered slides. These were relatively small slides, and the layer that slid was not very deep, but they can still carry you down the slope at their mercy if you are not careful. We continued to analyze the snowpack on slopes of various aspects and angles.
Another view of the slides - not very steep terrain. But steep enough to slide when disturbed by a skier.
Analyzing a wind loaded layer above suncrust. This top layer easily slid when disturbed.
Still, our eyes would catch signs of other skiers that had ventured above tree line and we would wonder about avalanche danger...although this was relatively low angle terrain.
Another pit, on a small slope that was on a different aspect, but very heavily wind loaded and deep. We were gathering more information from multiple sites...trying to build a more complete picture of snowpack stability.
It was now close to sunset and we had been standing in the shade for a few minutes. It was getting cold fast. Time to head back to the car over terrain that we deemed safe...and with enough vertical for a couple turns.
By this time there was not too much alpenglow to help light our way. It was good to be on the way back home.
Most of us rode in this van that dwarfed most pickup trucks!
Our final day of field training included a longer tour to a point below and northwest of Red Mountain #3 (pictured here). We climbed nearly a thousand feet above Red Mountain Pass, and reached the top of the treeline...where the effect of wind on snow was much greater. (Note: There is one skier and dog up near the top of this bowl...right of center.)
More snow pits! With more student participation and analysis!
A shovel compression test on a snow column about 12 x 12 inches and several feet tall. We were analyzing how different layers would fail under increasing loads (gentle taps, harder raps, etc.).
We also analyzed how smooth (or rough) was the layer that fractured, and the type/shape of snow crystals at that weak layer.
At the top of the treeline, where wind is stronger...snow pits only a few feet apart could tell very different stories...total depth, depth of weak layers, cohesive strength of strong layers, etc.
Lenticular clouds were forming over the San Juans. A weather system would move in tomorrow. But it meant that winds above treeline were strong. And you could enjoy nature's light show on the snowy peaks.
Sometimes the wind was strong enough to blow snow over us at the site of our final snow pit. We discussed all our findings from the tour up, and from all the snow pits...and decided it was safe to ski down through certain terrain. Time to rip off climbing skins and prepare for descent!
Travel down the mountain was sometimes as a group, sometimes singly...when passing near riskier terrain. Communication needed to be constant and complete.
Well below treeline, and in relatively safe terrain, we could take in the panorama of the San Juan mountains.
Here's a GPS trace overlayed on terrain in an oblique perspective view. Our tour was counterclockwise. Red Mountain #3 is the highest peak on the left.
As we neared our climbing goal, we had to switch back to avoid some steep and risky terrain.
Here's the route overlayed on a map so you can look at contour lines. Be safe out there and check the avalanche forcast before you tour! http://avalanche.state.co.us/