Avalanche Forecast

Issued: Jan 7th, 2019 5:00PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs and Loose Wet.

Jesse Percival,

Email
Main concerns: Storm Slab, Loose Wet.

Summary

Travel & Terrain Advice

Careful and continuous snow pack evaluation and cautious route-finding are key components to safe travel. Conservative decision-making is essential as reactive large avalanches will still be present. Expect to encounter on north aspects areas of extreme wind loading, be aware of these aspects and ensure to review and pick options that utilize terrain to avoid both features that promote deposition and create tension such as but not limited to convex rolls.

Avalanche Summary

Reports from avalanche control teams at Mount Washington indicate that ski cutting produced soft slab avalanches. These avalanches where small size one and triggered in isolated terrain on north and north west facing aspects.

Snowpack Summary

The snow pack received over a short period of time up to 150 cm of new storm snow. The accumulation is dependent on both the elevation and the location of terrain from west to east ( wet side to dry side ) of the island. Upper alpine areas have been stripped and pressed on south fading aspects and heavy loaded on north aspects. The snow-pack has had a chance to settle with mild temperatures and then allowed to “tighten up” or bond with a cooling trend.

Snowpack Details

Surface: variable surface conditions pressed and stripped to extremely well loaded. Upper: between 100- 150 cm of recent storm snow. Mid: December 22nd interface down 150 to 200 cm and is currently non reactive. Lower: well settled.

Past Weather

A series of winter storms brought to the region heavy precipitation amounts strong winds and rising freezing levels. In its wake freezing levels and temperatures dropped to near sea level and light to moderate precipitation in the form of snow fell with light to moderate wind.

Weather Forecast

Continued winter storms will alternate between periods of clearing and calm. Expect the temperatures and freezing levels to remain low. A surge late Tuesday early Wednesday will bring moderate east wind, moderate to heavy precipitation and rising freezing levels.

Monday Light flurries 5 cm freezing levels 250 meters and light south west wind.

Tuesday Clear and calm freezing levels near sea level light north east wind.

Wednesday 20 to 30 mm of precipitation freezing levels rising to 1500 meters moderate north east wind.

Problems

Storm Slabs

An icon showing Storm Slabs
Storm slab can be found on all aspects in the alpine and treeline and have had time to settle and bond with the cooling temperatures. These avalanche problems are still reactive to human triggers and are likely to be touchy to large triggers. If trigger a storm slab avalanche could produce a large avalanche up to size 3.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 3

Loose Wet

An icon showing Loose Wet
Tuesday into Wednesday, loose wet avalanches will be found on all aspects and elevations tree line and below. These avalanches will be touchy to human triggers and when trigger will be large, up to size 2.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Jan 9th, 2019 5:00PM