Avalanche Forecast
Issued: Mar 1st, 2018 3:00PM
The alpine rating is Storm Slabs and Cornices.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Low - Timing or intensity of solar radiation is uncertain on Friday
Weather Forecast
There is potential for a few more centimeters of snow on Friday, and then we move into a high and dry period. No significant precipitation is expected for the foreseeable future. FRIDAY: A few clouds in the morning, cloud building throughout the day, freezing level rising to around 900 m, light east/northeast wind, a few cm of snow possible. SATURDAY: A few clouds, freezing level rising to around 1100 m, light northeast wind, no precipitation expected.SUNDAY: A few clouds, freezing level rising to around 1200 m, light west wind, no precipitation expected.
Avalanche Summary
On Wednesday soft wind slabs up to 20 in depth were sensitive to human triggering to size 1.5. Wednesday night's storm likely initiated a cycle of natural storm slab avalanche activity.Small storm and wind slabs were sensitive to skier triggering Tuesday. Numerous skier triggered size 1 avalanches were reported from north and northeast facing features between 1450 m and 1900 m. We received a great MIN report of a large snowmobile triggered wind slab avalanche on the Brandywine Glacier that featured a 100 cm crown. More details available here.On Monday natural wind and storm slab avalanches to size 2.5 were observed on east/southeast facing slopes around 2000 m. A size 1.5 wind slab was skier triggered on an east facing alpine feature near ridgetop. A second storm slab was skier triggered on a northeast/east facing slope at 1900 m. Unsupported rolls at treeline were also sensitive to ski cuts producing very soft slabs 30 to 70 cm in depth.
Snowpack Summary
The Wednesday night storm produced far more snow than expected, 20 to 45 cm fell across the region accompanied by winds out of the east, southeast and south. In wind exposed terrain the new snow rests on widespread wind damaged snow and wind slabs that were formed by the weekend snow and strong to extreme winds earlier this week out of the southeast, south and southwest. In wind sheltered terrain the new snow may be sitting on a thin layer of surface hoar. The February 22nd interface is now down 50 to 70 cm, this layer is composed of old wind slabs, spotty surface hoar, facets and a sun crust on solar aspects. Snowpack testing on Wednesday continues to produce planar shears at this interface. As we move towards the weekend south facing slopes will be the most suspect with regard to this layer. Beneath the February 22nd interface the snowpack is well settled and strong. Variable winds in the past month have produced cornices on many ridgelines. They will become touchier as they grow in size, as temperatures rise, and when they are subject to the strong late-winter sun on clear days.
Problems
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Aspects: North, North East, East, South East, South, South West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 2nd, 2018 2:00PM