Avalanche Forecast
Issued: Mar 23rd, 2018 4:01PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
swerner,
Avalanche Canada
Ridgetop wind will switch from the East to the West forming reactive wind slabs on most aspects. Watch for whumphing and cracking below your feet and continue to make observations while gaining elevation towards alpine terrain.
Summary
Confidence
Moderate - Wind effect is extremely variable
Weather Forecast
Saturday: Mainly cloudy with possible sunny periods. New snow 2-6 cm accompanied by strong westerly ridgetop winds. Alpine temperatures near -3 and freezing levels 800 m.Sunday: Mix of sun and clouds with new snow 5-10 cm. Ridgetop wind strong from the southwest and freezing levels near 800 m.Monday: Snow up to 20 cm. Ridgetop wind strong from the South. Alpine temperatures near -2 and freezing levels 800 m.
Avalanche Summary
On Friday, several explosive triggered wind slab avalanches occurred up to size 2.5. Limited observations regarding aspect and elevation. On Thursday, several natural wind slab avalanches were reported up to size 2.5 from steep alpine features on northerly aspects.
Snowpack Summary
Up to 30 cm of new snow overlies a plethora of old snow surfaces including the March 9th and 19th surface hoar existing on high northerly aspects and a melt-freeze crust basically on all aspects at treeline and below. The new storm snow will initially have a poor bond to these buried interfaces. Strong easterly winds have redistributed the new snow onto leeward aspects forming thicker and likely more reactive slabs. Forecast weekend winds from the southwest will likely build new wind slabs on easterly aspects. Deeper in the mid-pack, layers of crusts, facets, and isolated surface hoar buried 50 to 100 cm exist from mid- and late-February and a surface hoar/ crust layer from January is buried around 150 to 200 cm. Near the bottom of the snowpack, sugary facets exist in colder and dryer parts of the region, such as the far north.
Problems
Wind Slabs
The new snow will likely have a poor bond to the plethora of old snow surfaces, especially where it sits on a melt-freeze crust or surface hoar on high northerly aspects. Changing winds from East to West will build wind slabs on most aspects.
Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.Use ridges or ribs to avoid pockets of wind loaded snow.Avoid large, unsupported terrain and slopes.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 24th, 2018 2:00PM
