Schuylkill Ridge near treeline

Location: Paradise Divide Area
Date of Observation: 03/27/2020
Name: Eric Murrow & Evan Ross
Subject: Schuylkill Ridge near treeline
Aspect: North, North East, East
Elevation: 8900 – 11400′

Avalanches:By early afternoon we could trigger quick running D1 Dry Loose avalanches on steep terrain running on crusts or stiff windboards.

Weather: Overcast skies with light snowfall. Snowfall rates picked up around 1pm to S1 rate. Winds were blowing from the southwest at the ridgetop transporting the new snow. New snow accumulations were 4.5 inches at 345pm (11,400′).

Snowpack: Ascended through shaded below treeline terrain up to 11,400′. Below treeline slopes had melt/freeze crusts on all aspects except those very close to due north. No signs of instability while ascending shaded terrain – found around 40cm snow above the 3/18 interface on sheltered slopes.

We dug a test profile near a recent avalanche – just one small terrain feature away. Expected to find a stout Wind Slab below ridge top, but dense wind-deposited snow tapered off quickly to just a few inches thick 20 feet below ridgetop. At this drifted site there was 65cm of snow resting above the 3/18 interface. ECT produced propagating results at three interfaces – an easy result beneath the stout windboard (from the recent wind event), a moderate result in a soft layer in the middle of the slab, and a hard result above the 3/18 crust (likely interface for the nearby recent avalanche). The column slid into the pit with energy above the 3/18 crust ‘cash register’ style. See profile photo.

We could easily produce Dry Loose avalanches in the 6 or so inches of new snow on the leeward side of the ridge. They quickly picked up speed on the old surfaces of melt/freeze crusts or windboard.