Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Unlikely - Possible
- Size
- 1.5–3
A persistent weak layer is buried 80 to 130 cm. This layer remains a concern where there is no thick, supportive crust under the recent snow.
Before entering avalanche terrain assess the bond of the new snow.
A persistent weak layer in the snow means avalanches could step down and become large.
A persistent weak layer is buried 80 to 130 cm. This layer remains a concern where there is no thick, supportive crust under the recent snow.
Up to 40 cm of recent storm snow combined with southwest winds has formed widespread and reactive storm slabs. The new snow will need a few days to settle and bond.
Wed/Thurs: Explosive control produced dry loose and storm slab avalanches to size 2 on north through east facing slopes. A natural size 2.5 storm slab was also observed.
Tues: A natural cycle of small (size 1 to 1.5) storm slab avalanches occurred.
Last weekend: Explosive control and natural cornice fall produced numerous slab avalanches up to size 2.
Looking forward: Storm slabs are expected to remain reactive and may step down to deeper persitstent weak layers.
Recent snowfall of 20 to 40 cm combined with southwest winds has formed widespread and potentially reactive storm slabs. Below 1900 m and on sun-exposed slopes, the new snow rests atop a melt-freeze crust left by previous warm temperatures and sun. The snow surface may be moist or crusty at lower elevations.
A persistent weak layer of surface hoar or facets from late January is buried 90 to 150 cm. This layer triggered large avalanches earlier in March, and remains reactive in snowpack tests. The greatest concern for this weak layer lies in areas where a thick, supportive crust is absent under the new snow. The lower snowpack is generally well-settled and strong.
Thursday Night
Mostly cloudy, with 1 to 5 cm of snow. 25 to 30 km/h southwest ridgetop wind. Treeline temperature -9 °C.
Friday
Partly cloudy, with trace amounts of snow possible. 20 to 30 km/h southwest ridgetop wind. Treeline temperature -7 °C.
Saturday
Cloudy, with 5 to 10 cm of new snow. 15 to 25 km/h south ridgetop wind. Treeline temperature -5 °C.
Sunday
Cloudy, with 1 to 5 cm of snow. 15 to 35 km/h southwest ridgetop wind. Treeline temperature -5 °C.
More details can be found in the Mountain Weather Forecast.