Persistent Slabs
- Hochgebirge
- Waldgrenze
- Unterhalb der Waldgrenze
- Wahrscheinlichkeit
- Possible
- Größe
- 2–3
Recent Avalanches: We heard from two groups that triggered small avalanches on the south end of Seattle Ridge yesterday; one was near the Headwall and the other was near Triangle Bowl. At least one of these was triggered remotely, and they were maybe big enough to bury a person. There was also one much larger avalanche triggered remotely near the Seattle Creek Headwall sometime since Thursday, which was around 1,000 wide and 1-2' deep. See Wendy's observation from yesterday for photos and some more info.
We are still seeing clear signs of concern from the weak layer of buried surface hoar that is anywhere from 1 to 3 feet deep and has been causing avalanches for almost three weeks now. Although it is slowly becoming more stubborn, people are still triggering big avalanches. This problem has been very hard to assess for a specific slope because it does not show up in every snowpit, and has been giving mixed results in stability tests. However, the fact that we continue to see people triggering large avalanches is all the information we need to know that it is still a major problem. We've also seen several avalanches failing on a more recent layer of surface hoar that was buried a week ago and is now around a foot deep.
Because of the unreliable feedback we're getting from snowpits, the only way we can really manage this problem is by avoiding steep terrain. If you are considering getting on steeper slopes it will be wise to choose low-consequence terrain, avoiding large slopes or anything above terrain traps like gullies, cliffs, or trees. This type of problem will often produce avalanches even after there are multiple tracks on a slope. We have also seen many avalanches triggered remotely, from low angle terrain adjacent to steeper slopes. This means you may be able to trigger an avalanche from the bottom of a slope, even when you are on flat terrain.
Glide avalanches are also still an issue and we have seen several recent glide avalanches release near Girdwood this week. Try to avoid traveling underneath glide cracks or expose one person at a time to minimize time underneath these unpredictable hazards.