Avalanche Forecast
Issued: Jan 23rd, 2016 7:38AM
The alpine rating is Persistent Slabs and Storm Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeA Special Public Avalanche Warning continues for this region. Conservative route selection and cautious decision-making is required.
Summary
Confidence
High
Weather Forecast
Sunday: Mainly cloudy with light snow. The freezing level is around 400 m and winds are moderate from the southeast. Monday: Periods of snow – 10-15 cm. The freezing level rises to 800-1200 m and winds increase to strong from the S-SW. Tuesday: Periods of snow. The freezing level is around 1000-1500 m. Winds remain moderate or strong from the SW.
Avalanche Summary
Observed avalanche activity varies throughout the region. Some reporters observed a fairly widespread avalanche cycle with numerous slabs up to size 2.5, mainly from slopes at and below treeline. Others reported only a couple natural slab avalanches up to size 2 from wind-loaded features. On Friday, there was one report of a size 3.5 slab that was remotely triggered by a helicopter touching down. Variable avalanche activity highlights the current challenges with buried and touchy persistent weaknesses.
Snowpack Summary
Light snowfall and steady moderate S-SE winds continue. Expect fresh wind slabs overlying older wind-affected surfaces in exposed lee and cross-loaded terrain. The January 9th surface hoar/facet layer down 50-70 cm in most places, and seems most concerning at and below treeline. Approximately 10 cm below this weakness you might find the Dec. 26/31 surface hoar layer. Reports of remote triggering, whumpfing, and sudden "pops" shears are all indications that both these layers could propagate well if triggered. Deeper persistent weaknesses buried in December have the potential to wake-up to heavy loading, rapid warming, or avalanches stepping-down.
Problems
Persistent Slabs
Buried surface hoar, now 60 cm deep on average, is primed for triggering. It's possible for light loads to trigger slabs even from relatively low angle slopes. Be extra cautious near treeline where surface hoar is more likely to be preserved.
Be careful with low angle slopes that may not normally be a concern.>Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Storm Slabs
Storm and wind slabs continue to grow. These slabs may be particularly touchy in exposed lee (W-NE) and cross-loaded terrain.
Choose well supported terrain without convexities.>Be cautious as you transition into wind affected terrain.>
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 24th, 2016 2:00PM