[高危]週末Alpine雪崩危機指數是紅色

North Shore Avalanche Report

Date Issued:   Friday, December 28, 2007 at 5:00 PM  
Valid Until:   Sunday, December 30, 2007  
The rating below is an assessment of the avalanche conditions as of the posted date. Avalanche hazard is subject to sudden change due to changing weather conditions and variation over terrain. The rating is provided to assist backcountry travelers in making their own educated decision as to whether travel is advisable. Individuals should make their own assessments before travelling into the backcountry.

Report of avalanche danger:    Friday
Alpine  
Treeline HIGH
Below Treeline CONSIDERABLE

Forecast of Avalanche Danger:   Avalanche Awareness Days are being hosted at all three North Shore ski hills on the weekend of January 12th and 13th. Come learn the basics of avalanche self-rescue or test your skills in the transceiver search. More details to be posted here.

Travel Advisory:
Anyone heading into the more open terrain at treeline over the next couple of days should be confident in their own stability evaluations and be prepared for self-rescue. Conditions are primed for recreational avalanche accidents at treeline elevations, so it is best to stick to simple terrain below treeline where the tree skiing is wonderful and more protected from the strong winds in the higher terrain. The North Shore received 50 cm of new snow in the past 24 hours. This snow has been transported by winds, forming thick soft windslabs on leeward slopes. Prevailing winds have been from the south; however, the intricate topography and micro-terrain on the North Shore means that mountaintop winds can blow in any direction meaning the soft slabs could exist on most aspects. Be very wary if you see shooting cracks or hear "whumpfs"- if the terrain you're in is capable of producing an avalanche then you're almost in one. Natural and human triggered avalanches are very likely on Friday, and even though conditions tend to improve rapidly on the North Shore, I would expect that many of the heavily loaded lee aspects that have not slid naturally will remain ripe for human triggered avalanches throughout the better part of the weekend.  
Avalanche Activity:   Several skier triggered avalanches big enough to bury a person were released Thursday and Friday. Soft windslabs varying in depth from 30-80 cm are running on mostly, but not exclusively, north aspects.  
Snowpack:   Several suspect layers exist within the snowpack including a thin solar crust from the 24th and multiple layers of graupel, but the most alarming instability is the development of wind slabs near ridgelines and open terrain. Windslabs vary in thickness and firmness, ranging from 30-80 cm.  
Weather:   An additional 5 cm of snow is forecast for Friday night accompanied by 20 km/hour winds from the west. A freezing level around 600 meters shows a slight warming trend. Saturday will bring 10 cm more snow with winds from the west at 20 km/hour and a freezing level of 500 meters. Sunday the snow will continue to fall with 10 cm expected. The freezing level should rise to 700 meters and will continue to rise into early next week.  

Prepared by:Rob Wilson

ALEXYIM
雪崩自救最基本工具:
beeper, probe, shovel