Avalanche Forecast

Archived

Jan 8th, 2019–Jan 10th, 2019

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

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The bottom line: Heavy snow and wind will create dangerous avalanche conditions on Wednesday. You can trigger large avalanches on wind loaded slopes near and above treeline. Carefully evaluate the snowpack and approach steeper terrain cautiously.

Snowpack and Avalanche Discussion

On Tuesday, observers witnessed large plumes of blowing snow at ridgetop in the Mountain Loop area. Several human-triggered avalanches were reported recently in adjacent zones. In the nearby Mt. Baker area, observers witnessed rapidly changing conditions on Tuesday afternoon as wind speeds increased and began transporting snow. On steep, wind drifted slopes, it was easy to trigger small avalanches 8-16in deep. Most avalanches were small, although some ran a few hundred feet downslope. Wind slabs will grow in size and distribution with significant snowfall and wind expected over the next 24 hours.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.