Archived

Avalanche Forecast

Jan 6th, 2015–Jan 7th, 2015

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

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: South Rockies.

Watch for fresh wind slab formation in wind exposed terrain.

Confidence

Fair

Weather Forecast

Synopsis: A battle between unseasonably mild Pacific air and cold air from the Arctic is underway Wednesday. The models are showing conflicting outcomes, but my best guess says the freezing level should remain near Valley Bottom. Confidence in the weather forecast is POOR. Wednesday: Freezing Level: Valley Bottom; Precipitation: Nil; Wind: Treeline: Moderate, SW | Ridgetop: Strong, W.Thursday: Freezing Level: Valley Bottom; Precipitation: Nil; Wind: Treeline: Light, Variable | Ridgetop: Light, W.Friday: Freezing Level: Valley Bottom; Precipitation: Nil; Wind: Treeline: Light, Variable | Ridgetop: Moderate, NW.

Avalanche Summary

Some surface sluffing was reported to have occurred in sheltered treeline areas on Monday. At higher elevations generally small wind slabs were also reported.

Snowpack Summary

Up to 19cm of recent snowfall has been shifted into wind slabs in upper elevation terrain by moderate to strong westerly winds. These new accumulations overlie hard wind slabs in exposed terrain, and low density faceted snow in sheltered areas. Up to 75 cm below the surface you will likely find a hard, thick crust which formed mid-December. This crust has overlying facets and surface hoar (up to 10 mm in sheltered locations at treeline and below). This layer seems variably reactive throughout the region. In areas where the overlying slab is thick and cohesive, large avalanches are possible at this interface. A crust/facet combo which formed in November seems to have gone dormant for the time being.

Avalanche Problems

Wind Slabs

Moderate to strong south/southwest winds Wednesday will likely form fresh and potentially reactive wind slabs. Watch for triggering in the lee of ridge crests and terrain breaks.

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

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Persistent Slabs

A crust which formed in December should remain on your radar as it has the potential to produce large avalanches. Dig down and test weak layers before committing to a line.

Stick to well supported terrain and be aware of what is above you at all times.>Avoid spots where you're more likely to trigger large deep avalanches: thin spots, rock out-croppings, convex rolls and broad planar slopes without anchors like trees.>Make observations and assess conditions continually as you travel.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 4