Summary
Travel/Terrain Advice
Avoid steep wind and storm loaded features especially as afternoon temps and freezing levels climb and certainly once the forecast rain begins to fall. This dangerous combination will potentially awaken the previous stubborn slabs. Small loose wet avalanches have the potential for high consequences near terrain traps. Avoid travel above cliffs, rocks and depressions. Steer clear of gullies where small snow amounts are magnified. Careful snowpack evaluation, cautious route finding and conservative decision making are key Thursday into Friday. Who wants to ski in the rain anyways?
Past Weather
No new snow in the forecast area with calm to light (5-17 km/h) variable direction winds. Daytime temps were mainly warm from 0-7 degrees in the alpine and treeline with cold temps only lingering in well shaded valley bottoms.
Avalanche Summary
Significant pinwheeling was observed on all aspects and elevations as freezing levels climbed over the past couple days. Trees were shedding their snow with the warm temps well up into the treeline. Intentional ski cuts produced small (size 1) loose wet avalanches at treeline at 1580 m on a NW aspect mid afternoon on January 1st on a steep unsupported slope in Strathcona Park.
Snowpack Summary
Surface - Rising freezing levels and warm temps during the day have caused moist surface conditions on all aspect and elevations. Possible cooling at night will produce a thin melt freeze crust.
Upper - Moist heavy snow overlies previous lower density (light and fluffy) storm snow in wind sheltered zones, and in open exposed areas at treeline and alpine moderate-firm wind pressed slabs cap the lower density snow giving it a scary hollow feel.
Mid - Well settled.
Lower - Well settled.
Weather Forecast
Warm air up high and cold air in the valley bottoms will begin to fade Wednesday into Thursday as south west flows bring mild pacific air up coast. With this new system significant precipitation is expected Thursday-Friday most likely in the form of rain to the top of our summits.
Wed - 0 mm. Winds light to moderate 3-15 km/h from the south east.
Freezing levels of 700-2700 m
Thurs - 5-15 mm most likely in the form of rain. Winds light to moderate 5-35 km/h from the southeast.
Freezing levels of 700-2700 m
Fri - 11-40 mm mainly in the form of rain, tapering to snow midday in the north and in the evening to the west and south. Winds strong south east tapering to light south 45-10 km/h.
Freezing levels of 1000-2300 m
Confidence
High- good alpine, treeline and below treeline observations, weather forecast models in agreement.
Problems
Wet Slabs
Areas previously loaded with storm and wind slab will see increased sensitivity to triggering as high freezing levels, warm temps and forecast rain moisten and saturate the upper snow pack. These slabs exist on all aspects in the alpine and on lee/north to west aspects in open and or wind exposed areas at treeline. While natural triggering is possible, human triggering is possible-likely with potential large avalanches up to size 2.5.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
Freezing levels will go above the highest mountain tops on the island and temperatures will be above zero. Rain will weaken the upper snowpack and these factors will result in possible natural triggered and likely to very likely human triggered small loose wet avalanches up to size 1.5 on all aspects and elevations especially in steep unsupported terrain, and zones of thinner snow.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 5th, 2018 6:00PM
