Big changes to the snowpack deserve big respect!
Winter returned to the high country. Heavy snowfall over the weekend dumped 90cm, while strong winds helped create surface slabs.
Time is needed for the new snow to bond with the underlying layers. Have patience. Allow the snowpack to adjust to the new load!
There are buried persistent weak layer (PWL) 's down 100-150cm in the snowpack, consisting of suncrust/facets/surface hoar. There is potential for step-down avalanches with the overlying storm slab triggering these deep layers, resulting in large, destructive avalanches.
90cm of snow, along with strong SW winds, has created a widespread storm slab that is reactive on all aspects and elevations. Natural and human-triggered avalanches are likely, given that this new slab sits atop a widespread surface hoar/suncrust layer.
A large natural avalanche cycle (up to size 3.5) began overnight Saturday and continued through until Monday am. Numerous avalanches reached the ends of their runouts.
Artillery control Sunday night produced avalanches up to size 4, with fast-moving powder clouds and slow-moving, spring-like wet debris.
A group up the Asulkan Valley triggered a size 2 avalanche Sunday, which partially buried one of their party members.
A big ol' dump! Up to 90cm fell on Fidelity over the weekend. This, combined with strong to extreme SW winds, has formed a widespread storm slab at all elevation bands. This slab is bonding poorly to old breakable crusts, widespread surface hoar, and sastrugi in the Alpine. Monitor this interface!
The two persistent weak layers (PWL) from Jan/Feb are now buried well over a metre. These could be step-down layers if the storm slab overloads them, resulting in large avalanches.
Unsettled weather ahead this week, with a weak front moving through Thurs.
Tonight Flurries, trace amounts. Alp low -10°C. Ridge winds SW 15-35km/h. Freezing level (FZL) 600m.
Tues Flurries, trace of snow. Alp high -6°C. Ridge winds SW 10-40km/h. FZL 1300m.
Wed Cloudy, isolated flurries. Alp high -2°C. Ridge wind S 25-35km/h. FZL 1800m.
Thurs Snow, 10cm. Alp high -3°C. Ridge wind SW 15-30km/h. FZL 1500m.
