Issued: Apr 2nd, 2023 4:00PM
The alpine rating is Wind Slabs and Cornices., the treeline rating is , and the below treeline rating is Known problems include
Recent new snow combined with wind has likely promoted fresh wind slab development at upper elevations.
A widespread avalanche cycle occurred yesterday, with small and large (size 2) storm slab, cornice fall, loose dry, and loose wet avalanches occurring throughout the region.
Skiers in the Shames backcountry triggered a slab avalanche 60 cm deep that occurred on a wind-loaded, north-facing slope. You can read the details here.
Several large (size 2) cornice falls occurred in the past week, most of which have not triggered slabs on the slopes below. However, there are a few exceptions where cornices did trigger large avalanches, including two avalanches north of Stewart on Tuesday (100 to 250 cm deep) and one avalanche north of Terrace on Thursday (30 cm deep).
Most areas saw 15-20 cm of new snow in the alpine yesterday, with up to 40 cm near Stewart. Snow totals rapidly taper off as you go down in elevation. New snow has formed reactive slabs in specific areas, such as near ridgecrest in the alpine.
In most areas this snow has covered a melt-freeze crust, except on shady slopes above 1500m where the snow has remained dry over the past week.
In most areas the lower snowpack is generally strong and well bonded. In outlying northern reaches of the region, basal facets may exist which are currently considered dormant. This layer may become active with abrupt changes to the snowpack, such as rapid loading (heavy snowfall or rain) or prolonged warming.
Partly cloudy, light to moderate northwest wind, freezing level dropping to valley bottom in most areas.
Mix of sun and cloud, chance of flurries with accumulations up to 5cm, light to moderate northwest wind, treeline temperatures high of -3 °C, freezing level rising to 700m.
Mostly sunny with increasing cloud, chance of flurries in the afternoon with trace accumulations, light to moderate west and southwest wind, treeline temperatures -5 °C to 0 °C, freezing level 500 rising to 1100m.
Mostly cloudy, 5 -10 cm of accumulation, moderate to strong south and southwest wind, treeline temperatures -5 °C to 1 °C, freezing level 500 rising to 1200m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Seek out sheltered terrain where new snow hasn't been wind-affected.
- Carefully evaluate steep lines for wind slabs.
- Caution around slopes that are exposed to cornices overhead.
Northwest winds are expected to form wind slabs on lee slopes and at ridgecrest.
The storm on Friday that brought 15 - 20 cm of snow came with southerly winds, so slabs may also exist on north aspects.
Aspects: North, North East, East, South East.
Beware of cornices. There have been a few large cornice collapses the past week, including some cases where they've triggered slabs on the slope below. Be extra cautious on slopes below cornices.
Aspects: North, North East, East, South East, North West.
Valid until: Apr 3rd, 2023 4:00PM