Regions
Northwest Inland.
We're in for a stormy week but it's hard to say how much snow or rain will make it inland. Avalanche danger could bump to high if you receive more than 30 cm of snow or it's raining steadily.
Confidence
Fair - Forecast snowfall amounts are uncertain
Weather Forecast
Synopsis: The storm track is aimed squarely at the Northwest this week. We’re certain to see some spillover into inland sections but the brunt will be felt right along the coast. Expect 10-20 mm of precipitation each day with the heaviest amounts possible on Friday. The freezing level should be gradually climbing to between 1500 and 1700 m. Winds are strong from the SW throughout the week.
Avalanche Summary
There were no new observations on Monday. A couple size natural size 2 wind slabs were reported from steep wind loaded terrain (northeast facing) on Sunday. Avalanche activity will probably be on the rise over the next few days with wet activity at lower elevations and wind and storm slabs above 1500 m.
Snowpack Summary
Strong southerly winds are building wind slabs, generally depositing snow on NW-NE aspects (other aspects may be getting cross-loaded or variable local wind effects too, so keep your eyes open). A surface hoar layer was reported to have been buried at the start of January in the northern part of the region. This may be around 20-40 cm deep now. In the mid-pack, a crust weakness buried in mid-December seems to have fallen off most operators' radar for now. Near the base of the snowpack is a November crust-facet combination that could remain problematic, especially in shallower snowpack areas with heavy loading and warming this week.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.