Friday February 22, 2019

Sunday February 24, 2019
Saturday February 23, 2019
Friday February 22, 2019
Confidence: Moderate - High degree of variability exists between forecast models for snowfall amounts in western and eastern zones of the forecast area.

Main Concerns

Persistent Slab, Wind Slab - view Avalanche Problems for detailed information.

Travel & Terrain Advice

Very dangerous avalanche conditions will continue to persist and travel in avalanche terrain is not recommended.

Avalanche Summary

Numerous loose dry avalanche from skier traffic up to size 1.5 has been reported at TL on Mount Washington.

Avalanche Problems

Persistent Slab

Down 20 to 40 centimeters facets can be found sitting on top of a very dense melt freeze crust. This avalanche problem is widespread can be found on all aspects and elevations and will be reactive to light triggers such a skiers. This problem is likely to produce avalanches to size two and may be possible to size three.

Wind Slab

Strong winds and available snow will encourage the development of these avalanche problems and will be found on predominately northerly aspects but can be found in isolated protected areas on all aspects. The elevations to find these avalanche problems will be In the alpine and at treeline. Wind slabs will initially be touchy to light triggers and may after time become less reactive as they begin to settle and bond. If triggered this avalanche problem will produce avalanches to size two.

Snowpack Summary

The upper surface of the snow pack is variable and includes, loose dry snow , areas scoured to crust and very dense wind pressed snow. The most concerning aspect to the current snow pack is that a layer of facets exists above a well developed and widespread melt freeze crust that is currently buried down between 20 and 40 cm. This highly reactive crust will gain further destructive potential with the incoming storm snowfall amounts and increased wind. Below the crust a well settled and dense coastal snow-pack exists.

Snowpack Details

SurfaceNew low density snow and a variety of surfaces from hard slab to exposed crust
UpperDown between 15 and 45 centimeter a weak layer of facets on a melt freeze crust and is found at all elevations and aspects
MidWell settled
LowerWell settled

Past Weather

Light snowfall and cool temperatures continued over the past forecast periods. A few daytime highs of above zero occurred , with winds being generally light out of the North east.

Weather Forecast

Friday: 10- 20 cm of new snow, Temperature -2 to +1, Moderate to Strong ridge top winds from the SW, Freezing Level 700 meters.

Saturday: 1-5 cm of new snow, Temperature -1 to -1, Moderate ridge top winds from the South West, Freezing Level 700 meters.

Sunday: Nil ,Temperature -2 to -9, Light to Moderate ridge top winds from the East, Freezing Level Sea Level.

Posted on Friday February 22, 2019 by Jesse Percival

Past Bulletins