Persistent Slabs
- Alta quota
- Limite del bosco
- Sotto il limite del bosco
- Probabilità
- Possible
- Dimensione
- 2–3
Recent Avalanches: On Saturday there were two groups that triggered avalanches around a foot deep on the south end of Seattle Creek drainage; one was near the Headwall and the other was near Triangle Bowl. At least one of them was triggered remotely and were reported to be big enough to injure a person. There was also a very wide propagating slab triggered near the Seattle Headwall sometime on March 13 or 14th, which was around 1,000 wide and 1-2' deep. We have not heard of any recent avalanches in the Seward zone but the snowpack is similarly concerning.
Today is looking to be cloudy and calm until around sunset when a weak storm rolls in bringing strong easterly winds and a few inches of snowfall. Until the winds pick up, around 4-5pm, the avalanche issues will remain status quo; meaning we are still tiptoeing around the mountains hoping not to trigger a large avalanche breaking on the Valentine's Day buried surface hoar that lurks 1-3 feet under our snowmachine/board/skis...
It has only been a couple days since the last avalanche was triggered on this layer, and 3-4 days since a large avalanche was triggered. These avalanches were all in the south end of Seattle Creek drainage. On the non-motorized side at Turnagain Pass it's been a week since the last known big avalanche (Eddie's). In the big picture, it's really not much time so our hackles are still up. Snowpit results are showing the layer to be stubborn and even unreactive, but the recent avalanches trump snowpit results. We have entered into the realm of 'not likely to trigger a big avalanche but it's still possible'. The consequences of triggering a big slab could be dire and that's what is keeping our danger elevated. Many of us are still using a very cautious mindset and sticking to low angle terrain.
To complicate matters a little, we've also seen several avalanches failing on a more recent layer of buried surface hoar that is now around a foot deep. Either way, the potential for triggering a large avalanche still exists and that's the main point. If you are considering getting on steeper slopes it will be wise to choose low-consequence terrain and avoid large slopes or anything above terrain traps like gullies, cliffs, or trees. These types of weak layers can produce avalanches even after there are multiple tracks on a slope. There have also been many avalanches triggered remotely, from low angle terrain adjacent to steeper slopes.
Glide avalanches are still popping out here and there. The most recent in the Girdwood Valley. A good reminder to keep a lookout for glide cracks and limit as much as possible being under them.
