Archived

Avalanche Forecast

Apr 10th, 2017–Apr 11th, 2017

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: 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.

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.

Avalanche 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