Quick report
- Collapsing
- specific
Today our team went out to Allison Creek to asses recent storm snow depth and reactivity throughout the area. Observations in the area included collapsing snow, active dry loose avalanches, and significant amounts of storm snow overlying weak layers in specific areas. Incremental snowfall over the last week has created more sensitivities within our snowpack than we have seen in a while. Weaknesses within the 40+ cm of recent storm snow are producing natural dry loose avalanches in specific areas. The Valentine's Day surface hoar, now buried 50cm deep, has not yet produced any avalanches but is becoming reactive in pit tests. Continued loadding or stiffening of snow overlying surface hoar may create an active avalanche problem on this layer in the future.
We witnessed a dry loose avalanche cycle on Mummy Mountain. Several D1- D2 dry loose slides were released in a short period from steep rocky terrain in upper elevations. Several collapses were experienced in flat terrain at around 1000 feet in elevation. Collapses were skier-initiated and could be heard traveling through connected terrain.Weather
- Air Temp
- 30
- Cloud Cover
- broken
- Wind Loading
- none
- Rain Elevation
- Old burried rain crust to 1500 feet.
- Recent Snowfall
- up to 40 cm recent storm snow
- Snow Avail For Transport
- large amounts
It was mostly cloudy with fog banks, snow squalls, and brief clearings moving through the area. Visibility was decreasing throughout the day. Temperatures were just below freezing at all elevations traveled. The recent storm snow started out dry at all elevations and became sticky and cohesive as the day progressed. No wind or signs of recent winds in the area.
Snowpack
Over the last week, small amounts of new snow at all elevations have been incrementally loading our snowpack. Today we are starting to see reactivity within and just below our most recent 15-40cm of storm snow. Several test pits were dug at a variety of elevations on our tour.
Below 1500 Feet:
Low ECTN scores (1-3) within the top 10-20 CM of unconsolidated storm snow. (Probably associated with dry loose activity in the area.)
ECTP12 within a crust-facet sandwich buried 40 cm deep. (Could be responsible for the collapses we felt)
Above 1500 Feet:
ECTN11 35 cm down within recent storm snow
ECTN 22 on buried surface hoar 50cm down at 2200 feet elevation.
Avalanche
At least half a dozen dry loose released off steep terrain on upper Mummy Mountain. D1-D2 Max size. No other avalanche activity observed.