Archived

Avalanche Forecast

Feb 4th, 2016–Feb 5th, 2016

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

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

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Glacier.

Another series of storms is bringing more snow, and more wind. It will also add to the load over a persistent weak layer. Be conservative in your terrain selection.

Weather Forecast

Today will be mostly cloudy with flurries. Moderate to strong S'ly winds will transport snow, loading lees. Temps should range from -6 to -12Â Overnight the next system will arrive, with 4cm overnight and up to 20cm by Saturday morning. Freezing levels are expected to remain below 1500m. Strong SW winds are expected to increase through the storm.

Snowpack Summary

In most areas, ~30cm of light snow overlies settled snow from last weeks storm. Tests indicate that as the new snow settles into a slab it may be triggerable. In some alpine areas wind slabs have developed on lee features after mod-strong S-SW winds. Jan 4th interface down 60-100cm and remains a concern in less traveled areas.

Avalanche Summary

No new natural avalanches were observed yesterday. On Tuesday, size 2.5 avalanches occurred from south aspects at ~2300m below Avalanche Peak as well as off of Mt Smart. Crisp crowns up ~1m deep with wide propagations indicate that they likely failed on the Jan 4th and were likely triggered by cornice fall or solar release from the cliffs above.

Confidence

Timing, track, or intensity of incoming weather system is uncertain

Avalanche Problems

Wind Slabs

Windslabs exist in some alpine areas, although they may now be hidden by the new snow. Be curious if you are venturing into the alpine; use your pole to probe into the snow and feel for windslabs and look for clues of wind-loading like drifts.

Use caution in lee areas. Recent wind loading have created wind slabs.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

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

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 2

Storm Slabs

Since last weeks storm ~40cm of snow is forming into a storm slab. With more snow expected over the next few days this slab is thick enough to be a concern. In many areas it is still loose however in some areas tests indicate this slab is triggerable

Be cautious of sluffing in steep terrain.Ride slopes one at a time and spot your partners from safe locations.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 1 - 2

Persistent Slabs

The Jan 4th layer is a lingering concern, and it is a tricky to assess. Where it exists it is down 60-90cm, but it is not evenly distributed & is sporadically reactive. It has been triggered recently by cornices, resulting in large avalanches.

Carefully evaluate terrain features by digging and testing on adjacent, safe slopes. Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 3