Avalanche Forecast

Issued: Feb 6th, 2018 4:12PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs and Cornices.

Avalanche Canada swerner, Avalanche Canada

Storm snow amounts will vary across the region. The Coquihalla will see higher amounts then the Duffy. If your local riding area receives more than 25 cm of new snow consider the danger to be HIGH on Wednesday.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Wednesday

Weather Forecast

The Coquihalla can expect 5-15 cm overnight Tuesday accompanied by strong westerly winds. Less expected on the Duffy.Wednesday: 5-10 cm of new snow through the day with another 15-25 cm overnight Thursday. Strong southwest winds at ridgetop elevations. Freezing levels near 1200 m. Thursday: Another 10-15 cm expected tapering off throughout the day. Ridgetop winds light with strong gusts from the southwest. Freezing levels near 1400 m.Friday: A mix of sun and cloud. Alpine temperatures near -12 with a high of -4. Light-moderate ridgetop winds from the northeast and freezing levels at valley bottom.

Avalanche Summary

On Monday, no new avalanches were reported. Evidence remains of last weeks widespread avalanche cycle up to size 3.5 from alpine features, below rock bands and thin snowpack areas. Forecast new snow and wind will likely build new storm slab problems Wednesday afternoon into Thursday.

Snowpack Summary

Recent snowfall totals are highly variable. In the south, up to 40cm of snow fell in the alpine over the past three days, while tree line elevations saw 10-20cm. In the north, new snow totals were 15-20cm in the alpine, and rapidly decreasing below 1800m.In the alpine, winds were moderate to strong from the south / east (Coquihalla) and moderate from the south / west (Duffey zone), creating fresh wind slabs in exposed downwind (lee) terrain. At lower treeline and below, warm temperatures (and rain in many locations) have created heavy snow and tough riding conditions.The new snow adds to the 80-150cm of snow that fell during the last few weeks of January. These series of storms were accompanied by strong to extreme winds which resulted in extensive scouring and impressive cornice growth in upper elevation terrain. These accumulations sit on crusts from early and mid-January which generally show signs of bonding to the overlying snow; however, a week ago they were sensitive to human triggering. With forecast snowfall and strong winds this deeper instability may wake up initiation large and destructive avalanches.

Problems

Storm Slabs

An icon showing Storm Slabs
New storm snow accumulations will build touchy storm slabs, especially on leeward slopes where more wind loading occurs.
Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.Stay off recent wind loaded areas until the snow has a chance to stabilize.Avoid avalanche terrain during periods of heavy loading from new snow and wind.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Cornices

An icon showing Cornices
Recent snowfall and strong winds have created fragile new cornices. These monsters may surprise with nasty consequences. Use extra caution around ridge crests.
Give cornices a wide berth when traveling on or below ridgesFalling cornices may trigger large avalanches on slopes below.

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Feb 7th, 2018 2:00PM