Avalanche Forecast
Issued: Jan 21st, 2021 1:00AM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
Ryan Shelly,
VIAC
No New avalanches reported this past week. Multiple sets of trip reports from recreational and professional personnel indicate some reactivity in the upper snowpack however these results also indicate a "stubborn" degree of sensitivity and are requiring major input (large trigger) in order to initiate these upper snowpack layers.
Please keep the observations coming! Thank you to those who took the time to post a MIN report or submit obs via our email forecaster@islandavalanchebulletin.com or via social media. It is much appreciated! Thank you Ben Godwin, SportNewK and Skafti and Theron Finley, Graeme and Joe for your reports.
Summary
Past Weather
Generally cool Temps (air temperature below zero) and a stagnant weather pattern (moderate winds and very little loose snow available for transport) as of late have contributed to an increasing trend in snowpack stability on Vancouver island.
Weather Forecast
Thursday: Very light precipitation expected (1cm Snow) , Winds Light from the North, Freezing level will reach a high of 850 meters.Friday: No precipitation expected, Winds Light from the North, Freezing level will reach a high of 700 meters.Saturday: No precipitation expected, Winds Light from the WSW, Freezing level 800M elevation
Terrain Advice
Be cognizant of snow conditions and utilize small slopes to test and investigate snowpack stability prior to stepping out into large slopes.Careful and cautious route finding when transitioning from scoured areas into areas of wind loaded snow. Avoid traveling below and above cornice features as they are large and generally unstable.Avoid open and steep slopes during periods of warming and rain; even small loose wet avalanches will have enough mass to push a mountain traveler into gullies and over cliffs.Currently we are experiencing generally safe avalanche conditions, particularly at the Below Treeline and Treeline Elevation bands however watch for unstable snow on isolated terrain features.
Snowpack Summary
A series of fluctuating air temperatures have created an array of upper snowpack melt freeze and rain crusts all within the upper 40-50cm of the snowpack. Within 5-10 cm of the upper surface, a relatively supportive crust exists and at the Below Treeline elevation band this crust is exceptionally dense and firm and provides challenging ski/snowmobile conditions until it softens (particularly at lower elevations (BTL)) with day time heating. Expect this crust to remain in place and firm/supportive as a result of generally cool air temperatures over the next several days.
Snowpack Details
- Surface: 5cm of soft decomposing new snow overlying a firm melt/freeze rain crust
- Upper: A series of rain and/or melt freeze crusts within the upper 50cm of the snowpack with new decomposing snow laminated between these crusts
- Mid: Well settled and it includes a dormant PWL (currently listed as unreactive) mostly due to bridging of 1.2M to 1.5M well settled snowpack above the PWL
- Lower: Well settled and dense.
Confidence
High - High confidence - based on high quality information and consistent weather over the past week has helped to render a solid judgement. Could benefit from additional Alpine elevation band snowpack observations.
Problems
Wind Slabs
Redistribution of snow due to wind was observed in the Alpine Elevation band. There remains a possibility for initiating small (size 1) to large (size 2) wind slab avalanches on specific and isolated terrain features particularly at the Alpine Elevation band.
Location: Found in Alpine and at upper Tree line elevation band specific to terrain just below ridge top and in down wind areas on steep unsupported (convex) terrain features.
Possibility: Triggering of this avalanche problem is possible from light loads such as skiers and snowmobilers. Natural avalanches are unlikely.
Size: If triggered expect these avalanches to be small, and in isolated areas, could be as large as size 2.
Likelihood
Expected Size
Valid until: Jan 22nd, 2021 1:00AM
