The wet, warm, and windy storm will result in High avalanche danger.
Summary
Confidence
Fair - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
Stormy conditions over the next few days. 10-15 mm of precipitation are expected Friday night combined with strong Westerly winds and freezing levels around 1600 metres. Another 10-20 mm of precipitation combined with very strong Southwest winds on Saturday as freezing levels spike up to about 2000 metres. The latest models are showing the Sunday storm moving faster and bringing another 10-15 mm of precipitation by late morning, and then becoming mostly flurries or showers as the freezing level creeps down below 1500 metres. Monday should continue to be mild with moderate winds and freezing levels dropping below 1000 metres.
Avalanche Summary
Periods of heavy snow or rain, strong ridge winds, and warming will probably tip off a natural avalanche cycle in parts of the region. We could see wet activity at lower elevations with storm/wind slabs where snow accumulates. There is also potential for deep persistent weaknesses to be overloaded producing isolated very large and deep slides.
Snowpack Summary
Warm temperatures have promoted rapid slab settlement and wet loose surface snow at lower elevations, while southwest winds continue to build slabs on leeward slopes with cornices overhead in exposed treeline and alpine terrain. A recent report from the Ashman area mentioned whumpfs and other signs of instability associated with roughly 30 cm of recent snow rapidly settling into a slab under warm temperatures and significant wind. A surface hoar layer buried at the start of January may be around 40-60 cm deep now. In the mid-pack, a crust weakness buried in mid-December seems to be unreactive for the time being. Near the base of the snowpack is the crust-facet combination buried in November that could remain problematic, especially in shallower snowpack areas with heavy loading and warming.
triley,
Avalanche Canada
