Avalanche Forecast

Issued: Mar 7th, 2015 7:34AM

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

rbuhler, Avalanche Canada

South Rockies.

Warm air temperatures with strong afternoon sun may destabilize the upper snowpack on south-facing slopes. Use extra caution on sun exposed slopes during the afternoon.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Warm and sunny is the theme for the next 3 days. On Sunday, mainly sunny conditions are expected with freezing levels reaching around 2000m. Alpine winds are expected to be moderate from the NW. On Monday, mainly sunny conditions are expected with freezing levels reaching upwards of 2500m. Alpine winds are again expected to be moderate from the NW. Conditions are currently forecast to be the same on Tuesday morning with increasing cloudiness during the afternoon.

Avalanche Summary

On Saturday, wet sluffing was reported from steep sun exposed slopes in the Lizard range. Similar conditions are expected on Sunday. Human-triggering of old wind slabs also remains possible in isolated areas.

Snowpack Summary

In sheltered areas, up to 10 cm of snow from earlier in the week sits over a previously variable snow surface which was a mix of surface hoar, crusts, wind affected surfaces, and/or dry powder. Ongoing winds have redistributed the new snow in wind-exposed terrain resulting in a highly variable snow surface and the formation of thin wind slabs in leeward features. The most prominent snowpack feature is a thick supportive crust around 10-30 cm below the surface. It extends up to around 2200m elevation. Below this elevation the crust is effectively capping the snowpack, preventing riders from stressing deeper persistent weak layers. In alpine areas where the crust is not present or is less thick, it could still be possible to trigger a deep avalanche from rocky sun-exposed slopes, thin snowpack areas, or with a heavy load (i.e. cornice fall).

Problems

Wind Slabs

Ongoing moderate winds from variable directions have created pockets of thin wind slab in exposed leeward terrain features.

Use ridges or ribs to avoid pockets of wind loaded snow.>Be cautious as you transition into wind affected terrain.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Loose Wet

Warming temperatures and solar radiation may cause sluffing on steep sun exposed slopes in the afternoon.

Avoid steep sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet. >Watch for clues, like sluffing off of cliffs, that the snowpack is warming up. >

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

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

Deeper weaknesses still exist and remain a concern in shallow rocky areas or anywhere the thick near-surface crust is weakening or non-existent, specially north aspects above 2200m.

Be aware of thin areas and rock outcroppings where it may be possible to initiate an avalanche that fails on one of the deeply buried weak layers.>

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Unlikely

Expected Size

3 - 6

Valid until: Mar 8th, 2015 3:00PM