SPRINGTIME AVALANCHE TIPS – Timing is everything
While many folks have already transitioned to summertime activities, there is still plenty of snow in the mountains. On any given day conditions can range from warm and sunny t-shirt weather to cold & snowy mid winter conditions. Being able to recognize and respond to specific avalanche concerns is key in making effective decisions in avalanche terrain.
Storm Snow & Wind Slabs
It is still possible to get significant snowfall this time of year. Pay attention to how much new snow has fallen and what surface it is sitting on. Is there a foot of new snow sitting on a crust? Even without a persistent weak layer between the slab and the bed surface, it is still possible to trigger dangerous slab avalanches. You can track new snowfall amounts by visiting the Turnagain Pass SNOTEL site. Ridgetop stations will allow you to figure out wind direction and speed. Knowledge of precipitation, wind and temperature data will give you a head start on your assessment before you even leave the house.
Loose Snow Avalanches
Both dry and wet loose avalanches are common springtime avalanche concerns. Pay close attention in steep terrain, especially when the sun first hits freshly fallen snow.
Cornices
We have yet to see any significant cornice falls this season. Many slopes have large cornices looming above them. Knowing exactly what will tip the scales is difficult. Some factors that contribute to cornice fall are sun, heat, and new snow with wind. Give cornices a wide berth and take measures to minimize your exposure to them.
Wet Avalanches
Wet slab avalanches are also a possibility this time of year. A combination of a slab, weak layer and water percolating into the weak layer is what is needed for this type of avalanche to occur. This combination will be possible in the higher elevations or after a storm deposits a new slab and rain or sun sends water down into the snowpack.
Below are some ways to both anticipate and deal with the above mentioned avalanche concerns:
• Watch for the “shed cycle” in the higher elevations. One great way is to keep an eye on the ridgetop weather stations (click HERE). Avalanche activity often follows multiple consecutive days (usually 3) of above freezing overnight temperatures. Careful route planning to stay out from under slopes with wet and rotten snow is essential during this period. This process has already taken place in the lower to mid elevations and is now confined to upper elevation terrain.
• Once the snow has undergone the transition to a summertime pack and is freezing at night and warming during the day (the corn season), hitting the slopes early and getting off them when they become too sloppy is critical.
• Damp or wet snow more than 6″ deep is a sign that it’s time to exit the area. Following the aspects as the sun heats up the slopes over the course of the day, East to South then West, can make for great riding/skiing days ending in sunny tailgating.
• Keep in mind, cloud cover ‘holds in the heat’ and can dramatically limit overnight refreezing. A shallow to no refreeze will not only give daytime heating a jump start on weakening the pack, but can produce less than stellar riding conditions.
• Beware of warm storms where rain is falling on snow, especially when rain is falling on cold dry snow. This can quickly increase the avalanche danger. €¨
• Stay off of CORNICES. When approaching from the side or above, make sure you can see where the cornice ends and the underlying terrain begins. If you can’t see that transition area, move away from the edge. If you find you and your group below cornices, expose only one person at a time and move efficiently through those areas.
• Lastly, don’t forget to plan your route back to the car. Does it take you under slopes that were frozen and safe earlier in the day, but now have been cooking in the sun waiting to slide on your return?
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