Observation: Public

Observation Details

Signs of Unstable Snow

Observations

Terrain: Parked at 2000ft on NF-1540 where continuous snow began. Toured up the winter route rib to 6200ft and descended NW slopes into the East Fork of Sibley Creek.

Avalanche: No new avalanches. A very large glide avalanche (WS-NS-R2-D3-G) occurred late last week on a north aspect at 3800ft. The avalanche released from a convex rock slab and ran 500 vertical feet with two lobes of debris (up to 10ft deep) crossing NF-1540 approximately .25 miles away from the Hidden Lake Lookout Trailhead. Other open glide cracks were visible above the same section of the road. Also observed 3 natural avalanches that ran during the February 22-25 avalanche cycle on the southerly aspects of Lookout Mountain and Pt. 5685 near Monogram Lake. Debris from one of these avalanches hit Cascade River Road (at the 1000ft level), while the other two came within 25-50 yards of the road.

Snowpack: 10-15cm (4-6in) of new snow above 4000ft well bonded to the 3/14 interface which presented as a supportable melt-freeze crust in most locations. Strong and settled snowpack below. Probing easily identified the Mid-January layer ↓250-300cm. Firm and icy snow surfaces exist in forested terrain below 4000ft (ski crampons were very useful).

Weather: Sky: Obscured, Wind: Calm, Precip: NO, Wind Transport: None. A thick cloud deck lingered near 3000-4000ft throughout the day with poor visibility and whiteout conditions above treeline.