Archived

Avalanche Forecast

Apr 13th, 2014–Apr 14th, 2014

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

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

2: Moderate

The avalanche danger rating below treeline will be moderate

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

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Northwest Coastal.

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Monday

Weather Forecast

Monday: Clear skies in the morning with increased cloud and light precipitation possible late in the day / Moderate southwest winds / Freezing level at about 1700mTuesday: Light to locally moderate snowfall / Moderate southwest winds becoming light and northerly / Freezing level at 1000mWednesday: Mix of sun and cloud / Light northerly winds / Freezing level at 1300m

Avalanche Summary

Although recent observations have been extremely limited, a solar induced natural avalanche to size 3 was reported on Saturday in the north of the region. Loose wet and slab avalanches were noted in this cycle with most activity occurring in steep terrain.

Snowpack Summary

Last week's storm brought 90+ cm or more to coastal regions forming thick storm slabs on leeward features. Warmer temperatures have helped to settle the recent snow, although the storm snow may continue to be touchy where it overlies surface hoar, crusts and/or facets buried at the beginning of April. Sun exposed slopes and lower elevation terrain is seeing a daily melt-freeze cycle and slopes below treeline are likely isothermal. Large cornices have formed and loom over slopes below.The early February crust/facet layer is down 150 - 240 cm. The weight of the recent storm snow and more recent warming have resulted in very-large avalanches at this interface.

Avalanche Problems

Storm Slabs

Snow and strong winds have built deep storm slabs at higher elevations. Continued warm temperatures and solar radiation will likely de-stabilize the new snow and natural avalanches remain possible. Destructive cornices may also fail with warming.

The new snow will require several days to settle and stabilize.>Minimize overhead exposure; avalanches triggered by warming or cornice fall may be large and destructive.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 4

Deep Persistent Slabs

Deep persistent avalanches would be very large and highly destructive. Possible triggers include cornice fall, a surface avalanche in motion, warming and intense solar radiation.

There is potential for large, deep avalanches due to the presence of buried facets and surface hoar.>Minimize exposure to overhead avalanche terrain, large avalanches may reach run out zones.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 3 - 7

Loose Wet

Watch for loose wet avalanches with daytime warming on steep, sun-exposed slopes. Loose wet avalanches can be pushy and entrain mass quickly.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 4