The storm snow is expected to be touchy on Monday, especially in wind loaded terrain and on steep slopes where it overlies surface hoar or a crust.
There is a lot of uncertainty regarding the intensity of the storm; check the bulletin in the morning for possible updates.
The new snow is expected to be most reactive in wind loaded terrain and places where it overlies surface hoar and/or a crust. Loose dry avalanches should be expected on steep slopes where the new snow has not formed a slab.
A storm system brings snowfall to the region Sunday night which may linger through the early part of the day on Monday. Modelled snowfall amounts and timing are highly variable which is creating a lot of uncertainty for conditions on Monday.
Sunday Night: Snowfall 15-25 cm, moderate to strong SW wind, treeline temperature around -6 C°.
Monday: Snowfall up to 5 cm in the morning, sunny breaks in the afternoon, moderate NW wind, treeline high around -4 C°.
Tuesday: A mix of sun and cloud, moderate NW wind, treeline high around -6 C°.
Wednesday: Mainly sunny, light variable wind, treeline high around -10 C°.
An early report from Sunday includes ski cutting triggering three size 1 wind slabs on NE aspects at around 2000 m failing on the Jan 14 SH down 20-30 cm. No new avalanches were reported on Saturday. On Friday, skiers triggered a few size 1 wind slabs on NE aspects around treeline. These were failing down 20-25 cm on the Jan 20 surface hoar.
The new snow is burying a highly variable snow surface which consists of wind affected surfaces in exposed high elevation terrain, a melt freeze crust at lower elevations and on solar aspects extending into the alpine, and/or widespread surface hoar in sheltered areas which is appears to typically be 5-15 mm but could be as large as 20-30 mm in places.
There are several crusts and surface hoar layers buried 20-40 cm deep. These layers have not been much of a problem recently but may become reactive with the additional storm loading.
A crust and facet layer near the bottom of the snowpack (100 to 200 cm deep) has been responsible for sporadic avalanche activity since early December. The layer has been mainly dormant in the region for the past couple weeks but still remains a concern. See the most recent forecaster blog for more details on this layer.
