The last system dumped more snow than forecast to parts of the region. If this pattern continues expect periods of HIGH avalanche danger over the next few days.
Summary
Confidence
Fair - Intensity of incoming weather systems is uncertain
Weather Forecast
Moderate to heavy snowfall or rain is expected to continue throughout the forecast period with 10-20 cm of snow (or mm of rain) each day for Friday, Saturday, and Sunday, although Friday is looking perhaps a little drier. Strong southwesterly winds are expected to ease off on Saturday and remain light to moderate on Sunday. Freezing levels around 1500 m on Friday are also expected to drop off to near valley bottom on Saturday, but fluctuate on Sunday.
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.
ccampbell,
Avalanche Canada
