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Avalanche Forecast

Mar 21st, 2016–Mar 22nd, 2016
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
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
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

Regions: Sea To Sky.

Conditions may change quickly in the spring. Even brief periods of sun can trigger pushy loose wet avalanches or promote destructive cornice falls.

Confidence

Moderate - Timing or intensity of solar radiation is uncertain on Tuesday

Weather Forecast

On Tuesday expect generally overcast skies with isolated flurries. On Wednesday a Pacific system will bring 10-20cm of new snow to the region. Light flurries are forecast for Thursday. Ridgetop winds will be light on Tuesday, and then become moderate and southwesterly with Wednesday's precipitation. Freezing levels should hover between 1200 and 1300m for the forecast period.

Avalanche Summary

On Friday, there was an anomalous size 2.5 slab avalanche on an unsupported rocky face on the northwest corner of Mt Fissile (in the Fitzsimmons Range) at about 1900m. Although the sliding layer is unknown, the avalanche was thought to have been triggered by warming. Over the past week there have also been numerous reports of solar-triggered cornice falls. Some cornice falls have been large (up to size 3), but most have only entrained surface snow. Explosives control ion Monday triggered storm slabs and cornice falls to size 2 in mostly alpine terrain.

Snowpack Summary

On Sunday night the region received between 12 and 30cm of new snow with highest amounts falling in the Southern Garibaldi/ Brandywine parts of the region. Moderate southerly winds formed soft slabs which seemed most reactive in lee alpine terrain. The new snow overlies a sun crust on sun-exposed slopes, dry settled powder on shady slopes and moist snow below 1800m. Below the new snow the snowpack is strong and well-settled throughout with no notable persistent weaknesses. Cornices are huge and fragile.

Avalanche Problems

Cornices

Some cornices are larger than a bus, and could easily collapse under the weight of a person or with daytime warming. Give these monsters a wide berth when traveling on or below ridge crests.
Extra caution needed around cornices with current conditions.>Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 5

Loose Wet

Brief periods of solar radiation are possible on Tuesday. If this happens, pushy loose wet avalanches will become a concern in sun-exposed terrain.
Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

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

Elevations: All elevations.

Likelihood: Possible

Expected Size: 1 - 3

Wind Slabs

New snow accumulations from Sunday night are expected to strengthen rather quickly. That said, new wind slabs may remain sensitive to human triggering in high elevation, wind-exposed terrain.
Be cautious as you transition into wind affected terrain.>Stay off recent wind loaded areas until the slope has had a chance to stabilize.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3