Avalanche Forecast

Fair - Forecast snowfall amounts are uncertain on Sunday

Significant storm arriving late afternoon or this evening. Strong SW winds, rising temps, precip rates of up to 8mm/hr expected. Looks like 30-40mm of rain below 1600m and 50-80cm snow above 1800m by late Friday. Saturday things slack off a bit: light -moderate snow, winds ease to light SW, and freezing levels drop to valley bottom. At the moment another pulse comes through Sunday but timing and intensity is uncertain. Stay tuned.

An early season cycle above 2400m on all aspects occurred in late October on the surface hoar layer. Mostly small soft slab avalanches from size 1 to 1.5 were noted. This layer still has the potential to produce more slides, especially between 1900 and 2400m. A small cycle of size 1.5 to 2 avalanches was noted Wednesday on southerly aspects. These were soft slabs that ran on the suncrust, producing impressive propagations on steep, unsupported terrain. Both these cycles have ended and only loose dry snow avalanche are occurring at the moment. This will all change very quickly as the current storm intensifies. I'm expecting a decent cycle starting late today or tonight involving the surface hoar and suncrust layers as well as a storm snow instability.

Average snow depth ranges from 110 (lower elevations) - 150cms (higher elevations). Below 1600m all areas are under threshold depth. 1600 - 1800m threshold has been exceeded only on smooth terrain. Above 1900m and early season snowpack exists with the potential for avalanches becoming a reality on most aspects and terrain features. Up to 50cm low density (40-50kg/m3) new snow and decomposing/fragmenting grains on the surface, settling rapidly with warm temperatures. This lies on a thin melt-freeze crust that formed on all aspects and elevations on November 9th when it warmed up for a day then cooled rapidly with the onset of the current storm. The mid-pack consists of 40 - 80cms or rounded grains that are settling and bonding well. These lie on a surface hoar layer that has been noted on most aspects above 1900m throughout the region where people have been poking around--admittedly the number of obs is relatively low but they have come from a variety of locations. The bottom 10 - 30 cms of the pack looks strong and well bonded considering how early in the season it is. Both the melt-freeze crust and surface hoar are layers to watch in the next few days as the coming storm looks to dump a decent load on the area. However, I expect both these layers will be shortlived. Check the Forecaster's Blog for a more detailed discussion of why I'm thinking along these lines.