Avalanche Forecast

Issued: Apr 10th, 2017 4:51PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Loose Wet, Cornices and Wind Slabs.

mgrist, Avalanche Canada

Lizard-Flathead.

The sun packs a punch these days - avoid south facing slopes on Tuesday if the sun comes out in full force. Limit your exposure to cornices when it's cloudy and completely avoid them when it's sunny.

Summary

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Some sunny breaks are expected on Tuesday, and then we're back to unsettled weather for the remainder of the forecast period. TUESDAY: Flurries Monday overnight (5-10cm possible) and then cloudy with sunny periods on Tuesday. Light southerly ridgetop winds. Freezing level around 1800 m.WEDNESDAY: Flurries late morning into the afternoon (5-10cm). Moderate easterly ridgetop winds. Freezing level around 1700 m.THURSDAY: Snow continues Wednesday overnight with 10-25cm possible by Thursday afternoon. Moderate southwest ridgetop winds. Freezing level around 1700 m.

Avalanche Summary

On Monday, several storm slabs and cornice triggered slabs to Size 2.0 were reported on northerly aspects between 1750m and 2100m. Some small, loose wet avalanches to Size 1.5 were reported on south facing aspects near 1750m in the afternoon on Monday.

Snowpack Summary

Since Saturday morning, 10-25 cm of new snow has fallen at treeline and above. The sun on Monday made snow surfaces moist and should stabilize quickly after an overnight refreeze. This new snow sits on a very hard crust up to 1400m (on north aspects) and up to 1700m (on south aspects).Moderate southwesterly winds have created wind slabs on lee features below alpine ridgetops. Cornices are large, looming, and best avoided.The snowpack is well settled and continues to transition into a spring snowpack, becoming isothermal at treeline in some areas and below treeline in most areas.The December facets and November rain crust are buried deep, but these deep persistent weaknesses have not been reactive for several weeks. That said, rapid warming of the snowpack or a large trigger, like a cornice, could trigger this layer.

Problems

Loose Wet

Sun exposure will cause loose wet avalanches, especially in steep terrain.

Use extra caution on slopes if the snow is moist or wet.Avoid exposure to sun exposed slopes.Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects: North, North East, East.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Cornices

Solar radiation is a common cornice trigger. Limit your exposure when it's cloudy and completely avoid cornices when it's sunny.

Minimize exposure to overhead hazard from cornices.Give cornices a wide berth when travelling on or below ridges.Cornices become weak with daytime heating, so travel early on exposed slopes.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 3

Wind Slabs

New snow and moderate southwest winds have formed wind slabs below alpine ridgetops.

Approach steep lee and cross-loaded slopes with caution.Be alert to conditions that change with elevation.Use ridges or ribs to avoid pockets of wind loaded snow.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Apr 11th, 2017 2:00PM