Bollettino valanghe Northwest Coastal — Dec 1, 2019

In sintesi

Caution as you transition into wind exposed terrain. Avalanches are possible in alpine terrain where wind slabs have formed.

Problemi valanghivi

Wind Slabs
N
NE
E
SE
S
SW
W
NW
Alta quota
Limite del bosco
Sotto il limite del bosco
Probabilità
Possible
Dimensione
1–2
Recent winds have likely left pockets of unstable snow in alpine terrain near ridgetop.

Weather Forecast

SATURDAY NIGHT - Mainly clear with isolated flurries / northwest winds, 20-25 km/h / alpine low temperature near -6

SUNDAY - Mainly cloudy with flurries, Up to 5 cm / northwest winds, 15-20 km/h / alpine high temperature near -4 / freezing level 700 m

MONDAY - Snow, 20-40 cm / southwest winds, 80-100 km/h / alpine high temperature near -1 / freezing level 900 m

TUESDAY - Mainly cloudy with flurries, Up to 5 cm / southwest winds, 30-50 km/h / alpine high temperature near -2 / freezing level 700 m

Avalanche Summary

A few small (size 1) naturally triggered avalanches were reported midweek. The main concern for human triggering is currently in areas where wind has blown surface snow into wind slabs.

Confidence

Low - Uncertainty is due to the timing, track, & intensity of the incoming weather system.

Snowpack Summary

Recent winds from the southeast have likely left wind slabs on north and east facing slopes at higher elevations. The snow from last weekend appears to have settled and gained strength, as shown by this MIN report from the Shames area on Wednesday. A total of 30-80 cm of settled snow from last weekend sits above a widespread crust. The snow has likely bonded to this crust, however given the lack of field observations there is still some uncertainty about whether this could be an interface capable of producing large avalanches. The total snowpack depth is around 100 cm at 1200 m, and is still below the threshold for avalanches in many areas below treeline.

Northwest Coastal

Pericolo valanghe