I saw the remnants of older natural avalanches that were unreported up to this point. Some of them are on or just outside our Hatcher Pass forecast boundary, but still worth noting. A common theme associated with them is that they originated on cross-loaded terrain features and are north through west in orientation. Some of these avalanches have the characteristics of failing on a persistent weak layer, assisted by the loading of wind transported snow. I have a few photos.
Observation: Hatcher Pass
Location: Sydney Creek
Nordic Splitboarded from Archangel Lot on the non-motorized groomed trail towards Sydney Creek. I toured in a popular sled/ski area on the small ridge just before you reach Sydney Creek. I found weak snowpack structure and excellent riding conditions.
Avalanche Details
Observer Comments
I found over 1 foot deep boot penetration.
Weather
Partly cloudy skies with a temperature of 5F degrees. In my location the winds were calm but to the east near Delia and Souvenir Peaks, the winds were strong and transporting snow from ridgelines.
Snow surface
Soft surface snow conditions with no wind affect.
Snowpack
A uniquely weak snowpack structure compared to most other places in the Hatcher Pass forecast zone. At the surface I found a Fist soft 25cm layer of snow from the 2/22 storm, unaffected by wind. There was a thin but easily breakable melt/freeze crust from the week of warmth 2/12-19. Just below that was a 2cm near surface facet layer which was my biggest concern for avalanches failing at. I tested this layer with minimal results: PST 80/100@88 SF & End; ECTN 23@7 (column caved in on itself @23); CT19 & CT21 @88 Brk. The snowpack structure was so weak in this area I could not hold a column of snow without it falling apart. The Lower snowpack was comprised of clustered Facets and chains of Depth Hoar. Upon descent I found a convex terrain feature where I easily sank, hitting rocks 2 feet below the surface.
Sydney Creek Snowpit 3/1/2024
Large Striated Depth Hoar Crystals found in a east aspect at 3150 feet 3/1/2024
Sydney Creek Snowpit 3/1/2024
Natural Avalanche in Archangel Valley from 2/22 cycle southeast aspect at 4000 feet
Natural Avalanches northwest of Divide Ridge west aspect at 4000 feet