Avalanche Forecast
Issued: Jan 26th, 2018 9:00AM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Loose Dry, Wind Slabs and Loose Wet.
Bill Phipps,
VIAC
Summary
Confidence
High - Forecast weather models are in agreement for the region and many days of field research.
Travel & Terrain Advice
Friday and Saturday watch for loose dry avalanches and wind slab. Avoid steep wind loaded terrain on NE-NW aspects in the alpine, treeline and open below treeline. Steep convex features and unsupported terrain are prone to release down to the firmer snow surface approximately 10-30 cm below. Use slough management to avoid being pushed by moving loose dry snow especially if exposed to terrain traps (like cliffs, depressions, tree stands, and rocks). Sunday….. Very high potential for rain to saturate our upper snowpack right up in to the alpine. This rain will lead to widespread loose wet and possibly wet slab activity. the hazard for this period will be high for all elevations and aspects so travel in all avalanche terrain is NOT recommended.
Avalanche Summary
Tuesdays strong to extreme winds pressed surfaces and loaded NE-NW slopes. Very limited visibility hampered avalanche observations, but we expect there was natural activity during this time due to wind loading. Wednesday temp dropped and the wind hardened surface tightened up and reduced activity. New snow Wednesday night and Thursday was moving easily with natural and human triggers. Natural slab avalanches were seen on NE asp at treeline up to size 1.5. Ski cutting, by Mt Washington avalanche control teams, produced numerous Loose Dry slides up to size 1 (running far and fast), a few size 1.5 soft slabs and one size 2 soft slab. All these ski cut results were treeline and below, on N to NE aspects, were in steep terrain to unsupported convex features and were the new snow running on the old wind hardened surface.
Snowpack Summary
10-20 cm of new snow sit poorly bonded to a firm wind pressed surface. Very high winds last Tuesday have transported significant quantities of snow to lee slopes and have left many wind sculpted features near ridge tops (snow drifts). Generally great sliding in enjoyable fresh snow!
Snowpack Details
10-20 cm of fresh with a couple thin crust like films (not noticeable while skiing) Lots of sporty wind features to play on. Upper: Firm windpressed snow (snow above bonding poorly to this). Mid: The big blizzard event (one meter plus) snow has settled down and seams to be nonreactive as cold temps have tightened it. Lower: Well settled.
Past Weather
Since the very high winds Tuesday, light to moderate snow had fallen. Temperatures have dropped significantly (-7 to -9.5 at times) and winds have been relatively light from the south east to north east.
Weather Forecast
light to moderate snowfall with cold temps and light to moderate winds from the SE-SW, freezing levels 200-850 m. Should be a great day to play!Saturday: light to moderate snowfall with cold temps and moderate to strong NE-SE winds, freezing levels 300-1000 m. Let the fun continue!!Sunday: moderate to heavy rain, light snowfall and even the possibility of light freezing rain, warm temps near +4 and very high winds from the south, freezing levels starting out at 600 and quickly rising to 2400 m. Not so fun!!
Problems
Loose Dry
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Aspects: North, North East, East.
Elevations: All elevations.
Likelihood
Expected Size
Loose Wet
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 27th, 2018 9:00AM
