Tyson wishes he could ski steep winter powder. I want to feel confident we are making safe choices when we ski Colorado next month. So we signed up for a three day AIARE 1 avalanche class out of North Conway.
Given the fancy name, I thought it would be more technical, but it turned out to be a refresher of the class Jed taught us 9 years ago. In the intervening years, Tyson and I bought our own beacon, shovel, and probe, but didn’t venture into avalanche conditions. This weekend’s class had 6 students and one instructor, John. There was a 20 year old and his dad. The son was the more enthusiastic AT skier of the two. Both of them had summer experience hiking the Whites. Neither had avalanche training. The other two students were ski partners from Boston and Connecticut. Their off resort skiing experience was guided tours in the Rockies and the Alps. As a result, they had almost no planning skills or observation skills.
The first day we covered beacons and rescues. Honestly, I would much rather learn to avoid an avalanche in the first place than practice rescues. The new things I learned were
- go slower than you think you need to for last 10m
- a person feels squishy when you probe them
- terrain features may block the transceiver signal
In our indoor discussion, we covered general planning.
For a location you plan to ski
- know the types of avalanches to which it is prone
- track the snowpack and weather over the season
For each trip
- identify the hazard(s)
- plan alternate routes and decision points
- make emergency plans (Leader/2nd. Who has which group gear. Phone numbers. Nearby shelters/evacuation help.)
On the second day, we got deeper into snow science.
For an avalanche to happen you need
- terrain steep enough to avalanche
- unstable snow pack
- a trigger
Dry avalanches move faster than wet avalanches. Dry avalanches may create a wind blast in front of them, and may jump ridges or small mountains. Wet avalanches move slower, but they may slide on shallow slopes (20 degrees vs 30+ for dry), and they have a longer runout.
Things to watch out for with terrain
- slopes 30+ degrees
- lee or cross loaded aspects
- trigger points (convex bulges and thin/perforated spots)
- terrain traps (funnels and strainers)
- run out zones
- is the terrain challenging group’s capacity to the point they aren’t observing well.
We focused on snow pack instability as it relates to slab avalanches. I didn’t understand how to predict the other type of avalanche — loose or point release avalanches. Slab avalanches happen when the snow has a stronger layer above a weaker layer or interface. An avalanche happens when a trigger initiates a fracture and the fracture propagates. That being said, even if you only find initiation tendency, consider it dangerous and go somewhere else.
We can measure the instability of the snow pack with a snow pit. Pick a spot with the same orientation and elevation as the slope you want to ski
- 1.2m deep because humans can usually only trigger 1 meter down.
- poke wall to find layers. Measure hardness with fist/fingers/pencil
- 30x30cm column test.
- 30x90cm extended column propagation test
The smoother we made our walls, the easier it was to see cracks. And by “we” I mean Tyson since I couldn’t shovel properly with my hand in a cast.
The snow can rapidly become unstable if
- snowing more than 6″ in 24 hours
- wind creating wind slabs
- rapid warming of previously virgin frozen snow. Like up to 50F in one day.
We practiced more rescues with beacons that day. In each scenario, a students played the role of group leader, and the instructor joined as a participant. Once we had the hang of things, the instructor assumed the role of clueless saboteur. The two guys who had only gone skiing with guides were shocked. They finally caught on by the end of the day.
Why are we here?
Sunday evening, Tyson and I stopped for dinner at the open restaurant in Bartlett. The food was inoffensive. I hardly noticed given our conversation.
“If the avalanche danger is considerable tomorrow, why bother going up to the ravine? We already know it is too dangerous to ski.”
“What is the point of taking the avalanche class if we just stay home? John has lots of experience, and even if he can’t convey it well in class, we can learn by watching him make decisions in real conditions.”
“I don’t want to die in an avalanche.”
The young guys in the neighboring booth stopped chatting. I imagined them eavesdropping.
“I don’t want to die in an avalanche either. But I do want learn when it’s safe and when it isn’t. That distinction is so fuzzy right now that I have to leave a huge margin.”
“Reducing your margin increases your risk of getting caught. I am not willing to be as risky as John. Remember his story of an avalanche going by and then casually stepping left onto the avalanche path because that was safer than staying on the fresh snow.”
“I don’t intend to take risks. I want an accurate assessment of whether a slope is dangerous or not. You point at a slope and say ‘It has snow on it. We shouldn’t ski it.'”
The waitress brought out our pizza and disposable plates.
“Do you remember soft learning vs hard learning? With soft learning, mistakes have very small repercussions. Whereas with hard learning, you mess up once and you are done.”
“In car racing, I found I got the most feedback when I pushed the limits. If we stay far away from avalanche terrain, we can’t learn anything.”
“So how do we learn safely and not rely on luck?”
We went around and around. We decided we could learn from hands on practice the different characteristics of snow, and how to read terrain from far away. We would need to learn from experts which snow and terrain make avalanches. I later read something similar in the AIRE 1 student handbook
Before starting, professionals identify what they expect will happen, actively engage in a process to continually assess what is happening, and then compare what actually happened to what they thought would happen.
Day 3. Field day
On the third day of AIARE 1, the class goes out and practices in real terrain. Saturday morning, the avalanche forecast for Mount Washington was moderate, with wind slabs from the mid-week storm. Saturday evening it snowed 4″ in the valleys. The mountain avalanche danger went up to considerable and it kept snowing. Unsurprisingly, the avalanche forecast for Monday was considerable. Not a day to go into avalanche terrain.
My other concern was the cold – highs in the mid single digits F, and 50mph winds. With my broken thumb, I would be standing around getting cold while everyone else worked up a sweat digging pits. I brought every jacket and mitten I owned and fit over my cast. Plus I borrowed a huge mitt from the instructor. Then I ate and ate and ate to ensure I had the fuel to keep myself warm.
It’s amazing how fast a group of adults can hike up to Hermit Lake. We reached the cabins at 10AM. 4 hours earlier than a typical Isaac trip. And 2 hours earlier than an AMC trip. Our instructor had a different philosophy on snack breaks than the AMC. As a trip leader, I usually announce a 15 minute food/water/bio break whereupon everyone dons extra jackets to stay warm. This instructor instead called 3 minute breaks. Just enough to get a handful of snacks or a swig of water. Then we were off before anyone could get cold.
From Hermit Lake, we skied over to lookers left of Hillman’s. I had expected that to be a dangerous spot because it was the run out for several avalanches last year. John said it was not dangerous because lower Hillman’s was still mostly rocks. And there wasn’t enough snow above to jump the ridge.
I was surprised we saw no sign of avalanches in Tuckerman’s. The instructor pointed out avalanche debris in the lower snowfields. To me it looked old, but he said it was fresh.
We dug our snow pits. As expected, we found wind slabs at top and then several ice layers below. When we did the column test, the weak faceted depth hoar at bottom didn’t give way. The instructor said the ice layers on top protected it. That meant it was not an avalanche concern.
The group decided it was too cold and windy to ascend towards main ravine. Had we gone up, our instructor said that at every view point, he would have stopped and evaluated.
Then we skied down and debriefed. Next year we should take AIARE 2.
Photos from the field trip