Avalanche Forecast
Issued: Feb 18th, 2018 4:54PM
The alpine rating is Wind Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Moderate - Wind effect is extremely variable
Weather Forecast
Clear and cold for the foreseeable future, with overnight lows near -25 Celsius in some locations. Monday: Mainly sunny. Tree line temperature around -15 Celsius. Winds light northerly.Tuesday: Sunny with cloudy periods. Tree line temperature around -12 Celsius. Light winds northerly. Wednesday: Cloudy. Tree line temperatures around -12 Celsius. Winds moderate westerly.
Avalanche Summary
On Sunday we received reports of an initial wind slab (size 2) stepping down to deeper weak layers and triggering a size 3.5 persistent slab, on a south west aspect near 2300m.On Saturday, explosives control work produced several storm slab avalanches to size 2.5 on a wide range of aspects near tree line. In Rogers Pass a week ago, skiers remotely triggered a size 3.5 persistent slab avalanche from 40 m away on a south-facing, cross-loaded slope at 2600 m. Although deeper, persistent avalanche activity is becoming less frequent, there is still potential for these layers to react.
Snowpack Summary
30-50 cm of recent storm snow is settling into a slab in the upper snowpack. Strong winds, most recently from the north / east, shifted these accumulations into deeper, reactive slabs in wind-exposed terrain. The more recent snow sits on a mix of older wind slabs in exposed higher elevation terrain, a sun crust on steep solar aspects, a rain crust below 1600m, and surface hoar on sheltered slopes.Below the snow surface, several persistent weak layers make up a troublesome snowpack. In the top 1.5-2.5 m of the snowpack, two surface hoar layers buried in January can be found. Expect to find one or other of these on all aspects and elevations.Deeper in the snowpack (around 200 cm deep) is a facet/crust/surface hoar layer from December, most prevalent at and below treeline.Near the base of the snowpack is a crust/facet combo, most likely to be triggered from thin spots in the alpine.All of these layers have produced large avalanches recently. The wide distribution and ongoing reactivity of these layers suggests that avoidance through choosing simple terrain is the best strategy.
Problems
Wind Slabs
Aspects: North, North East, East, South East, South, South West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 19th, 2018 2:00PM