Dangerous avalanche conditions exist at alpine and treeline elevations. Fresh snow sits over a persistent slab problem, at a prime depth for human triggering large, consequential avalanches. Avoid wind-loaded areas and stick to simple, lower-angle, supported slopes with no overhead hazard.
A crust formed in early January has been bonding poorly to the overlying snow. With the recent new snow load, this crust is now buried 60-80 cm deep, a prime depth for human-triggering as well as large, consequential avalanches.
Strong southerly winds and overnight snowfall have created touchy fresh slabs. Storm slabs may be most reactive where wind has loaded deep deposits into leeward terrain features in the alpine and treeline.
No new avalanches have been reported in recent days with limited travel and visibility in the mountains. We suspect a natural avalanche cycle to have occurred during periods of heavy loading from snow/rain and wind.
Looking forward to Monday, potential remains for human-triggered avalanches. A crust formed in early January is now buried 60-80 cm deep and has the potential to produce large and surprising avalanches.
Above 1000 m, consistent recent snowfall has deposited 60-80 cm over a slippery crust layer while rain has soaked the snowpack at lower elevations.
Snowpack depths at treeline are around 100 cm, tapering quickly with elevation to below threshold for avalanches at most elevations below treeline, except for isolated smooth features such as rock slabs and grassy slopes.
Sunday night
Rain or wet snow, 10-20 mm for most areas 30+ mm on the western side of the island. Ridge wind strong south 70 km/h. Alpine low of -2 °C. Freezing level 1000 m.
Monday
Cloudy in the morning with rain/snow starting in the afternoon, 5-10 mm. Ridge wind strong from the south 60-80 km/h. Alpine high of -1 °C. Freezing level 900 m.
TuesdayOvernight rain/snow 5-10 mm, up to 20 mm for the west coast. Skies clearing in the afternoon. Ridge wind easing to moderate southeast. Alpine high of +1 °C. Freezing level rising 1400-1700 m.
WednesdayMostly cloudy with flurries starting in the afternoon. Ridge wind increasing to strong south. Alpine high of 0 °C. Freezing level 1100 metres.
More details can be found in the Mountain Weather Forecast.
