Wednesday February 12, 2020

Friday February 14, 2020
Thursday February 13, 2020
Wednesday February 12, 2020
Confidence: High - Weather models in agreement and good field data.

Main Concerns

Wind Slab - view Avalanche Problems for detailed information.

Travel & Terrain Advice

Avoid wind loaded open slopes at treeline and in the alpine as new snow Thursday into Friday will be transported, creating the potential for wind slab avalanche activity. The bond of these new slabs to the exposed old crust below will be very suspect. Keep an eye out for those “tricky to see them coming” openings in the forest that create treeline like features at lower elevations, as wind slabs will be present once the snow and wind starts. Even though we are in winter, the below treeline snow pack is still shallow and many creeks, holes, rocks, roots and stumps are lurking on or just below the surface. Travel with care and slow down as you move into the lower elevation zones.

Avalanche Summary

No new avalanches have been reported since Sunday Feb 9th.

Avalanche Problems

Wind Slab

Lingering wind slabs from last Fri/Sat storm still exist in the alpine and open treeline. More new snow Thursday into Friday will add to and create new wind slabs in the alpine and treeline. These slabs will be on N-E-SE aspects and cross loaded features and have the potential to have a weak bond to the exposed crust zones they will fall on. Natural triggering is possible and human triggering is possible to likely from size 1 up to size 2 avalanches.

Snowpack Summary

Little to no new snow has fallen since the storm Friday Feb 7th into Sat Feb 8th. Over the past few days we have moved into a more spring like melt (during the day) freeze (overnight) cycle. Variable surface are present depending on aspect and elevation. Ridge tops are scoured to the old crust from the monsoon rain event on Jan 31, storm snow from last Fri Sat is still nice in wind sheltered non solar pockets, SE and NW alpine and open treeline elevations have pockets of wind slab from the Fri Sat storm and strong winds and finally…. Solar aspects treeline and below have a new thin melt freeze crust.

Snowpack Details

SurfaceVariable surface conditions from old wind slabs, exposed old crust, preserved snow to a new thin sun crust
UpperFri Feb 7 to Sat Feb 8ths storm snow (bonding moderately well) over the thick and supportive Jan 31 rain crust
MidMoist snow well settled with a few old crusts
LowerWell settled

Past Weather

Little to no new snow with temps ranging from just below 0 (overnight) to +8 (during the day).

Weather Forecast

Very light rain Wednesday changing to light to moderate snowfall Thursday through Friday with some wind transport expected.

Wednesday - 0.1 to 2 mm of rain below 700-900 m, falling as small amounts of snow above. Winds light from the SW. Temps -2 to +2. Freezing levels 900-500 m.

Thursday - 4 to 14 cm of new snow (lower amounts for East/Washington, moderate amounts for North/Cain, deepest for West/Strathcona). Winds moderate to strong S to SW. Temps 0 to -4. Freezing levels 900 to 1000 m.

Friday - 1 to 8 cm of new snow. Winds light to moderate SW to NW. Temps -2 to -6. Freezing levels 700 to 900 m.

Posted on Wednesday February 12, 2020 by Bill Phipps

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