Persistent Slabs
- Hochgebirge
- Waldgrenze
- Unterhalb der Waldgrenze
- Wahrscheinlichkeit
- Likely
- Größe
- 2–3
Recent Avalanches: On Saturday there were two human triggered avalanches around a foot deep on the south end of Seattle Ridge near the Headwall and in Triangle Bowl. At least one of them was remotely triggered. A large avalanche was reported on the Seattle Headwall that was 1,000’ wide and 1 to 2’ deep, likely releasing on March 13 or 14.
The incoming storm will make it easier to trigger a large avalanche on a layer of surface hoar buried 1 to 3’ deep. 4 to 8” of snow is expected accompanied with strong southeast winds gusting to 50 mph in the afternoon. Portage may receive almost 20” of snow. This will increase the chance of triggering a large avalanche on a layer of buried surface hoar above 1,500’ on all aspects.
Today is not the day to get on or under steep slopes. The simple reason is that this storm will add stress to this weak layer and that people are still triggering large avalanches. Many of these avalanches have been remotely triggered meaning that people have triggered avalanches above or adjacent to them from low angle slopes. Snow tests are unreliable because they can give stable results on the same slopes we are seeing avalanches. Slopes with tracks on them seem safe yet we are still seeing avalanches after multiple people have ridden the slope. On the non-motorized side we have not had a large human triggered avalanche in a week, the last one being on Eddies, BUT people have not been getting into steep terrain. It is likely that if they do, human triggered avalanche activity will increase. This is why we are asking people to dial it back. Even with mixed field information, large avalanches are still occurring. Rather than trying to outsmart this problem it is safer to enjoy soft snow in less consequential terrain away from steep overhead slopes.
Cornices will be growing all day increasing the chance they fall and trigger an avalanche above you. This is another reason why today is not the day to travel below steep slopes. If you cannot avoid them try to spend as little time under them as possible.
Glide Avalanches: Glide cracks will likely be hard to see today. They are still releasing as glide avalanches so try to avoid traveling under them. If you do encounter one, spend as little time underneath them as possible.
