Friday April 12, 2019
Loose Wet, Wind Slab
Travel & Terrain Advice
Avoid exposure to all large steep slopes in the treeline and below, during daytime warming (no solar faces when the suns out or temps rise above freezing) or when/if rain saturates the upper snow pack on big terrain.
Stay way from and give terrain traps a wide berth during warm and or rainy times (cornices, gullies, cliffs, depressions, creeks, bands of trees…).
Keep off wind loaded N to NE avalanche terrain in the alpine and treeline elevation bands during and after the storm (Saturday into Sunday). Give the winds slabs, that will form, a bit of time to bond and settle to the old snow and crust that they will form on.
Numerous small loose wet avalanches were reported off steep rocky solar exposed cliff faces at all elevations over the past three days, as one would expect as warm spring temps are now reaching up higher into the mountains.
Watch for potential wet loose avalanche activity Friday as temps rise and the sun pops out. These avalanches, though small (up to size one), when combined with terrain traps can be dangerous. They will be possible to trigger with human activity and will be sensitive to triggering on all aspects except the north. They will most likely be found in the below treeline and treeline elevation bands.
Saturday into Sunday a storm with moderate snow fall amounts and high winds (from the S to SW) comes in. This storm will result in wind slab formation in the alpine and treeline. These slabs will have a sensitivity to triggering in the possible to likely range with human activity and a potential avalanche size range of size 1 to 2.
10 to 20 cm of new moist snow fell above 1000 m over the past three days on top of a crust that formed prior.
|Surface||moist new snow|
|Upper||a breakable crust over well settled moist warm storm snow from last weekends blizzard|
Clear, sunny skies and positive temps Tuesday warmed the upper snow pack then cooled at night creating a crust. 10 to 20 cm of new moist snow fell early Wednesday morning fallowed by a few flurries Thursday.
Mild Friday with a moderate storm event forecast for Saturday into Sunday.
Friday - 0 to a trace of new precip, winds light SW, temps 0 to 2, freezing level 1500 to 1700 m
Saturday - 7 to 15 cm of new snow, strong S winds easing to moderate SW, temps 0 to -4, freezing level 1000 to 1400 m
Sunday - 2-4 cm of new snow, light SW winds, temps a cool -2 to -4, freezing level 850 to 1100 m
Posted on Friday April 12, 2019 by Bill Phipps