| Trigger | Unknown | Remote Trigger | Unknown |
| Avalanche Type | Unknown | Aspect | Southeast |
| Elevation | unknown | Slope Angle | unknown |
| Crown Depth | unknown | Width | unknown |
| Vertical Run | unknown |
Avalanche: Turnagain
Location: Seattle Creek Drainage
Afternoon ride up the motorized up-track and into the higher terrain along the Seattle Ridge headwall. We were targeting the hottest part of the day. Despite this, there was still a lot of crusty conditions encountered along with some roller balls on steep south slopes.
Avalanche Details
Noted three recent looking slab avalanches that likely occurred yesterday (March 19). One of these looked like it was triggered by a wet loose avalanche. The other two looked to be slabs that the sun triggered by heating them up to the point of failure. They were likely still fairly dry and not your text book wet slab. Wet slabs by definition have water lubricating the interface between the slab and weak layer. See photos.
Observer Comments
Recent avalanches and a warm afternoon.
Weather
Sunny!
Temps around 30F.
Light west breeze on ridge.
Snow surface
Crusty...
Shaded slopes had a wind/warm weather crust about an inch thick.
Solar slopes had a 1-2" melt-freeze crust, much thicker near the parking lot.
By the afternoon some south aspects warmed enough to melt the surface crust, but this was more the exception.
Snowpack
We dug one snow pit at 3,300' on a northeast aspect under the Seattle Headwall on the west side of the drainage.
Pit depth was 3.5 feet, total snowpack depth was 10 feet. We had no results in our pit (ECTX). We did find the buried surface hoar 2 feet deep that has been responsible for many human triggered slabs over the past week. It was a good sign that it was fairly stuck in this location, but it has still been reactive in other locations.
The BSH was 3-5mm in size and was sandwiched between pencil hard snow above and below.
The storm snow has settled to 2 feet from 3-4 feet and is very dense now.
Sun triggered slab avalanche likely from yesterday, March 19.
Two more sun triggered slabs, one right looks like it might have been triggered by a small wet loose avalanche.
Snow pit at 3,300' on a NE aspect, No results, weak layer did not fail
Surface conditions on more shaded slopes were crusty too. A new crop of surface hoar is growing, you can see the glittering on the surface
This south aspect was still soft, the top 1-2" was in the melt phase but was soon to start refreezing
Classic Seattle Ridge photo looking north from BBQ hill
Looking over the motorized parking lot to Tincan and Kickstep. This lot will hopefully be filled with you all on Saturday for our Avy Awareness Day! Noon to 4pm March 23.