Avalanche Forecast

Issued: Mar 18th, 2019 4:12PM

The alpine rating is high, the treeline rating is high, and the below treeline rating is considerable. Known problems include Loose Wet and Persistent Slabs.

cgarritty, Avalanche Canada

Northwest Inland.

This is a good time to avoid avalanche terrain.

Summary

Confidence

Moderate -

Weather Forecast

Monday night: Clear. Light to moderate south winds. Freezing levels remaining near 3200 metres.Tuesday: Sunny with a chance of valley cloud. Light south winds. Aline high temperatures around +5 with freezing levels of 3000 metres, remaining steady overnight.Wednesday: Mainly sunny with a chance of valley cloud. Light east or southeast winds. Alpine high temperatures around +5 with freezing levels around 2800 metres, lowering a bit overnight.Thursday: A mix of sun and cloud with cloud increasing over the day. Light south winds. Alpine high temperatures around +3 with freezing levels around 2300 metres, lowering a bit overnight.

Avalanche Summary

There are few observers in the field this week but reports showed a natural avalanche cycle of storm and wind slabs up to size 2 early in the week and loose wet avalanches with afternoon warming.

Snowpack Summary

Up to 50 cm of snow arrived in the past week. This recent snow rests on previously wind affected surfaces, sun crusts (on solar aspects) and weak, sugary facets. The prolonged period of cold temperatures in February has had an overall effect of weakening the upper and mid-snowpack, as well as the basal snowpack in thinner areas.Sunshine and warm temperatures will weaken the upper snowpack; the difficult question is how quickly this will affect deeper layers. One answer is the thinner the snowpack depth, the quicker it will happen.

Problems

Loose Wet

Sunshine and warming will destabilize surface snow - especially on steep, sunny slopes. This problem is likely to expand to include shaded aspects under sustained warming. Large loose wet avalanches may impact lower elevations.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Be aware of loose wet avalanche problems expanding to shaded aspects as warm temperatures persist.Be aware of overhead hazards and avoid exposure to avalanche runout zones.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Persistent Slabs

Old weaknesses may reactivate under sustained sunshine and warming. There are numerous reports of large slab avalanches in neighbouring areas, some of them remotely triggered (see Northwest Coastal). Expect similar potential in the Northwest Inland.

Remote triggering is a concern, watch out for adjacent slopes.If triggered, storm/wind slabs may step down to deeper layers and result in even larger avalanches.The chance of persistent slab avalanches will increase as warm temperatures persist.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1.5 - 3

Valid until: Mar 19th, 2019 2:00PM