Archived

Avalanche Forecast

Mar 29th, 2013–Mar 30th, 2013

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

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

Regions: Northwest Inland.

Be alert to conditions that change with daytime warming. Danger ratings may exceed posted levels when solar radiation is strong.

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

No precipitation is expected for the forecast period. Although high cloud is forecast on Saturday, generally clear skies are expected on Sunday and Monday.Winds will be light from the west on Saturday, generally calm on Sunday, then switching to light and southwesterly Monday.Freezing levels will hover at about 1300m on Saturday, 2400m on Sunday and then 1900m on Monday.

Avalanche Summary

Numerous loose wet avalanches have occurred from steeper solar aspects up to size 2.0. Size 2 cornice releases have also been noted. A size 2 natural was also reported in Morning Bowl in the Hankin area. It reportedly failed down to rocks in shallow places on a convex roll. I would expect more of this activity with forecast warming.

Snowpack Summary

Surface snow has settled with the influence of warm temperatures and surface hoar is growing on shaded slopes. Solar aspects and lower elevation terrain are now well into a daily melt-freeze cycle. 30 - 60 cm of snow overlies a crust, old wind slabs or surface hoar layer buried on March 9th. Reports suggest this layer is less reactive, but may still be a concern in some areas. The distribution of the surface hoar is also highly variable and it may not exist in every drainage. I would still remain conservative and continue to dig and test before diving into my line. Deeper in the snowpack, basal facets may resurface as a concern with forecast warming.Cornices have become well-developed and could easily become unstable during periods of warm weather or direct solar radiation.

Avalanche Problems

Loose Wet

Clear sunny skies and warmer afternoon temperatures will promote deterioration within the upper snowpack. If surface snow becomes moist or wet, loose wet avalanches are likely.

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: Likely - Very Likely

Expected Size: 1 - 4

Cornices

Large cornices will likely become weak if the sun is shining. Cornice failures may be destructive by themselves and may also initiate avalanches on the slope below.

Cornices become weak with daytime heating, so travel early on exposed slopes.>Pay attention to overhead hazards like cornices.>

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

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 6

Persistent Slabs

Spotty surface hoar buried on March 9th may be reactive in some drainages. Dig down and test layers before committing to big lines. Deep weakness that formed early season may also resurface as an issue with forecast warming.

Carefully evaluate big terrain features by digging and testing on adjacent, safe slopes.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2 - 5