Avalanche Forecast
Issued: Mar 12th, 2017 5:46PM
The alpine rating is Storm Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Moderate - Forecast snowfall amounts are uncertain on Monday
Weather Forecast
Monday: Scattered flurries bringing up to 5 cm of new snow, transitioning to rain below 1500 metres in the afternoon. Moderate to strong southwest winds. Freezing level rising to 1900 metres over the day. Alpine temperatures of -1 to 0. Tuesday: Isolated alpine flurries, rain showers below around 1600 metres, intensifying overnight. Moderate south winds. Freezing rising to 2000 metres over the day with alpine temperatures of 0 to +1. Wednesday: Continuing alpine flurries and rain showers below 1500 metres. Strong southwest winds. Freezing level dropping to 1500 metres over the day with alpine temperatures of 0 to -1.
Avalanche Summary
Reports from Saturday include one observation of a Size 1 persistent slab releasing with a ski cut on an east aspect over the mid February weak layer in the Hurley area. Several more Size 1 slabs were reported releasing on northerly aspects in the north of the region under a range of triggers, including natural and remote.Reports from Friday showed several wind slabs failing naturally and with remote triggers from Size 1-2.5 in the north of the region. The largest of these initiated on a southeast aspect at 2100 metres, is suspected to have failed on the late February weak layer, and featured a crown fracture depth of 80-120 cm.Reports from Thursday included one explosives triggered Size 3 avalanche in the Duffey Lake area that began as a shallow surface slab before stepping down to one of our February weak layers. Looking forward, recent persistent slab avalanche activity supports ongoing concern for large avalanches releasing on our February weak layers, especially in the north of the region. While natural avalanches on these layers may become unlikely, evidence suggests the possibility for a rider to directly trigger a persistent slab or for a smaller avalanche to 'step down'.
Snowpack Summary
A week of stormy weather has brought 80-120 cm of recent snow to the north of the region and roughly 150 cm to the south. Recent south to southwest winds have redistributed much of this snow in wind-exposed terrain, forming touchy wind and storm slabs. The above mentioned storm snow overlies the mid-February and late-February interfaces, which may be close together in the snowpack. The late-February interface consists of wind affected surfaces in exposed terrain, sun crust on steep solar aspects, and facets and surface hoar in sheltered areas. The mid-February interface consists of a thick rain crust which extends to at least treeline, a sun crust on steep solar aspects, and in many places, a layer of facets overlying the crust. Recent snowpack observations and avalanche activity suggest the late-February layer is most reactive in the north of region while the mid-February layer may be becoming unreactive in the south of the region. Below these layers, the mid and lower snowpack are generally well settled and strong.
Problems
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 13th, 2017 2:00PM