Archived

Avalanche Forecast

Mar 6th, 2018–Mar 7th, 2018

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

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: Northwest Inland.

The sun can pack a punch this time of year. Be aware of signs of deteriorating stability such as snow pin-wheeling down slopes or small point-release avalanching below cliffs.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

WEDNESDAY: Mix of sun and cloud / Light northwesterly ridgetop winds / Alpine high of -9THURSDAY: Mostly sunny / Light southwesterly ridgetop winds / Alpine high of -9 FRIDAY: Mix of sun and cloud / Strong southwesterly ridgetop winds / Alpine high of -3

Avalanche Summary

On Sunday, a few size 2 natural avalanches were reported on north and east aspects in the Howsons. A few large (up to size 3) cornices failed on east-facing slopes and triggered slabs on the very steep slopes below.A MCR report from the Howsons (see here) reports widespread wind slab activity (size 1-2) during the peak of the storm last week and a decrease in activity by the weekend. A similar cycle of natural wind slab avalanches was also reported north of Hazelton. Although wind slab activity has declined, human-triggering remains possible.

Snowpack Summary

Moderate to strong outflow winds have redistributed 50-70 cm of recent storm snow in exposed areas. This storm snow has buried hard wind affected snow in exposed areas as well as sun crusts or dry facets in sheltered terrain.A crust/surface hoar layer buried mid-January is now roughly 80-140 cm below the surface, and still has the potential to be triggered from a thin snowpack spot, or with a large trigger like a cornice fall.It is unlikely, but may still be possible to trigger very large avalanches on facets at the bottom of the snowpack in steep, rocky, and shallow snowpack areas or with large triggers.

Avalanche Problems

Wind Slabs

Strong winds from a variety of directions over the weekend have redistributed snow into wind slabs on all aspects. Steep, convex, and rocky areas are the most likely spots to trigger these lingering wind slabs.

Watch for newly formed wind slabs as you transition into wind effected terrain.Be aware of the potential for wide propagations due to the presence of hard windslabs.Use ridges or ribs to avoid pockets of wind loaded snow.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 2