Avalanche Forecast

Archived

Jan 6th, 2019–Jan 7th, 2019

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

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The Bottom Line: Pay attention to areas where the wind drifted the new snow into firmer and thicker slabs. It’s these wind affected areas where you will be more likely to trigger an avalanche. If you see drifted snow, fresh cornices, or snow pillows you can stay safe by avoiding nearby wind loaded slopes greater than 35 degrees.

Snowpack and Avalanche Discussion

We received reports of several human triggered avalanches from adjacent zones on Sunday. In the Mt Baker backcountry, these avalanches occurred within the new snow and were generally small. However, one larger avalanche on Mt Herman reportedly ran for several hundred feet down the slope. We saw two common themes in these human triggered avalanches. One, they occurred in areas where the wind drifted the snow into slightly firmer slabs. Two, many of the avalanches were triggered near convex rollovers in the terrain.

At lower elevations, recent and significant liquid water will make travel challenging. Watch for glide cracks, exposed rocks and creeks, and expect a refreezing upper snowpack.

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.