Avalanche Forecast

Issued: Apr 10th, 2019 4:01PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs and Loose Wet.

swerner, Avalanche Canada

Northwest Coastal.

Natural avalanche activity is likely when temperatures rise and the sun comes out. Especially in areas that have received new storm snow. If it remains cloudy in your local riding area the danger rating is MODERATE.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

Unsettled weather leading into the weekend with a mix of sun and cloud and some convective precipitation. The next frontal system will hit the coast Saturday.THURSDAY: A mix of sun and cloud with alpine temperatures near 1 degree and freezing levels 1400 m. Ridgetop winds light from the northeast.FRIDAY: A mix of sun and cloud with alpine temperatures near 1 degree and freezing levels 1300 m. Ridgetop winds moderate primarily from the southwest.SATURDAY: Snow amounts 5-10 cm. Alpine temperatures near -1 and freezing levels 1100 m. Ridgetop winds will generally be light with strong gusts from the southwest.

Avalanche Summary

Reports on Wednesday indicated no recent avalanche activity. A combination of new snow and wind may increase the reactivity of the existing wind slabs. The sun can really pack a punch this time of year and trigger loose wet avalanches especially in areas with fresh snow.

Snowpack Summary

5-10 cm of snow fell at upper elevations on Tuesday night. This brings 20-80 cm of recent snow which sits above a weak layer buried April 4th. This layer consists of a crust, surface hoar and facets. The crust is widespread and up to 4 cm thick. Spotty surface hoar and facets have been reported on top of the crust on high elevation north facing slopes. Fresh wind slabs may remain sensitive to human triggering especially on the higher elevation northerly aspects and the new storm snow will likely be reactive once the sun shines though.Â Digging deeper, north facing alpine terrain also has a layer of facets down approximately 100 cm below the surface, but this layer has not been recently active and is likely trending towards dormancy.Below treeline the snowpack is isothermal and in some places below threshold throughout much of the forecast region.

Problems

Wind Slabs

Up to 60 cm of snow has accumulated above a widespread crust. Strong southerly winds have likely formed fresh slabs in high elevation north facing features. Human triggering is most likely in the immediate lee of ridgecrest.

Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.Back off if you encounter whumpfing, hollow sounds, or shooting cracks.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Loose Wet

Periods of sunshine may initiate a loose wet avalanche cycle in the new snow. The likelihood of loose avalanches increases as temperatures warm through the day and/or if the sun comes out for a period of time.

A moist/wet snow surface, pinwheeling and natural avalanches all indicate a weakening snowpack.Loose avalanches may start small but they can grow and push you into dangerous terrain traps.

Aspects: South East, South, South West.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 1.5

Valid until: Apr 11th, 2019 2:00PM