Date/Time issued:
Thursday, January 01, 2009 at 3:00 PM
Valid until:
Sunday, January 04, 2009 at 6:00 PM
Next Scheduled Update:
Friday, January 02, 2009
Friday
Alpine ~ ~ ~
Treeline 3 - CONSIDERABLE
Below Treeline 2 - MODERATE
Confidence: Poor. There is some uncertainty about the track, timing, and extent of the low-pressure system forecast for Saturday night.
Primary Concerns:
* Storm Snow: Around 100cm of new snow has fallen since December 28th. Lingering storm snow instabilities could be susceptible to triggering by the weight of a person.
* Wind Slab: 25cm of new snow sits on a variety of hard and soft windslabs on exposed slopes at all elevations and aspects.
Special Message: Happy New Year from the forecasters at the CAC! Please continue to check back for daily updates throughout the holidays.
Travel Advisory: Issued: Thu, Jan 1 Next Scheduled Update: Fri, Jan 2
We should see a brief break in the weather on Friday and possibly Saturday. Travel conditions have improved considerably with over a meter of new snow that is much more supportive. Cool and dry weather should allow for a decrease in the avalanche danger; however, don't let the powder and sunshine tempt you into making hasty and careless decisions. Watch for obvious signs of instability like recent avalanches, whumpfing or cracking, and moist surface snow from sunshine. If these signs are present then it's best to stick to simple terrain. Avoid steep solar aspects in the middle of the day, large and steep convex rolls, and traveling in or above terrain traps. We are expecting conditions to rapidly deteriorate on Saturday night with the arrival of an intense frontal system.
Avalanche Activity: Issued: Thu, Jan 1 Next Scheduled Update: Fri, Jan 2
Several size 1-2 avalanches were observed on NW aspects on Wednesday afternoon and ski testing produced several small slab avalanches up to 30cm deep on Thursday. In southern Garibaldi Park on Tuesday, a skier on a NE aspect near ridge top intentionally triggered an avalanche that was large enough to bury or kill a person. This avalanche released on a thin layer of surface hoar, down approximately 80cm. This area has a very similar snowpack structure to the North Shore, and similar avalanches are possible on steep open slopes at higher elevations.
Snowpack: Issued: Thu, Jan 1 Next Scheduled Update: Fri, Jan 2
Around 100cm of snow has fallen during recent storms. This brings the average snowpack depth to around 200cm. Consistent strong SE-W winds have created areas of hard and soft windslabs and wind-pressed snow in all exposed terrain. A feathery surface hoar layer, down 80-100cm, is still producing moderate to hard "pops" shears. It may be possible for a small avalanche to step-down to this layer in smooth open slopes at higher elevations.
View Avalanche Observation Summary (NEW!)
Weather: Issued: Thu, Jan 1 Next Scheduled Update: Fri, Jan 2
Northwesterly flow should result in cold and dry conditions on Friday. The freezing level should drop to sea-level and mountaintop winds should be NW 20-40km/h. Periods of flurries or snow should develop on Saturday with an accumulation of 10-15cm. An intense frontal system should reach the South Coast on Saturday night and bring heavy snow, strong winds, and slight warming. We could see 40-60mm of precipitation in a mix of rain and snow as the freezing level briefly rises to 1500m.
Prepared by: Peter Marshall