Archived

Avalanche Forecast

Mar 22nd, 2018–Mar 23rd, 2018

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

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

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.

Storm slabs will likely be reactive. Ridgetop wind will switch from the East to the West forming wind slabs on most aspects. Stick to simple terrain first while gathering observations.

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

Overnight Thursday: New snow 5-10 cm accompanied by strong easterly winds and freezing level at valley bottom.Friday: Cloudy with 3-7 cm of new snow. Ridgetop winds light gusting strong from the northwest. Alpine temperatures near -8 and freezing levels 600 m.Saturday: Mix of sun and cloud. Ridgetop wind strong from the West. Alpine temperatures near -7 and freezing levels 900 m.Sunday: Mix of sun and cloud. Alpine temperatures near -7 with freezing levels near 900 m. Ridgetop winds mostly light with strong gusts from the West.

Avalanche Summary

On Wednesday there was evidence of lower elevation glide slab releases.With forecast snow and wind you can expect the avalanche hazard to rise.

Snowpack Summary

Up to 15 cm of new snow with another 10-15 cm in the forecast is expected overnight. The new snow will likely have a poor bond to the underlying snow surface which consists of surface hoar on northerly aspects in higher elevation bands and firm melt-freeze crusts. In the mid-pack, a surface hoar and crust layer from January is buried around 80 to 140 cm in the southwest of the region. This layer still has the potential to be triggered from a thin snowpack spot, or with a large trigger like a cornice fall.Sugary facets exist at the bottom of the snowpack in steep, rocky, and shallow snowpack areas.

Avalanche Problems

Storm Slabs

New snow will bond poorly to the plethora of old snow surfaces. It could step down deeper to the surface hoar layer buried March 9th. Uncertainty remains around the distribution of this layer. Changing winds will build wind slabs on most aspects.

Stick to simple terrain and be aware of what is above you at all times.Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Very Likely - Certain

Expected Size: 1 - 2.5