Observation: NWAC Forecaster

All Observations

Basic Information

Observation Date:

March 11, 2023

Submitted:

March 11, 2023

Observer:

NWAC Forecaster - Dallas Glass

Zone or Region:

West South

Location:

Crystal Backcountry, Kahuna Peak, Norse Peas (All aspects below and near treeline. (3900-6700ft))

Recent Avalanches?

Yes

Cracking?

None Experienced

Collapsing?

None Experienced

Classic signs of wind loading and a shallow wind slab crown. E. 6200ft.

Up track tests routinely highlighed hidden wind affected snow with long (10-12ft) cracks. N, 5800ft.

Subtle changes in aspect made a big difference in wind loading.

Shallow wind slab crown below a wind loaded cliff feature. ESE 6000ft.

An old cornice triggered slab avalanche. ESE, 6000ft

Old avalanche debris in Goat Basin. Several inches of snow cover the debris pile. N aspect.

Piles of rollerballs and small loose wet avalanche occurred on steep S slopes below treeline later in the day.

Surface hoar was plentiful in many slopes at all elevations.

Advanced Information

Cloud Cover:

Partly Cloudy

Wind:

Light , S

New/Recent Snowfall:

New Snow: (HN24) 2-3 in (5-7cm)

The weather was pretty dynamic today. Periods of light snow fall and near zero visibility would shift to mostly clear skies and sunshine.

Avalanche Observation Comments:

Wind Slabs: There were signs of a few (~4-5) shallow wind slabs that looked like they occurred yesterday (?) or the night before. These were typically on NE-SE aspects below cornices or cliffs.

Loose Wet: I was able to trigger a 2 small (D1) loose wet (push-o-lanches) at 4200ft on a S aspect around 230pm.

Wind: There were plenty of signs of wind transported snow: scoured slopes, blowing snow, cornices, textured surfaces, drifts, snow knocked out of trees, and firm pillow-like slabs. Many of these signs extended down into the top of the below treeline area. Most of the wind slabs I encountered were very firm and some felt hollow (hard slabs). While they didn't fail on small slopes, they did occasionally fail on up-track tests. In these locations small (2-4mm) surface hoar was found below the slab. Based on the firm nature of the slabs, I stayed out of larger steep wind loaded features.

With wind slabs prevalent throughout the terrain, the upper snowpack has a bit of an up-side-down nature to it now. We only found deep soft snow in very sheltered and treed terrain.

The sunshine and warm temperatures caused mostly piles of roller balls form steep rocky southerly terrain (at all eleavtions) and open slopes below treeline. A new crust has formed on these sunny slopes.

A fresh crop of surface hoar was found in most open areas away from ridgecrest.

Problem	Location	Distribution	Sensitivity	Size	Comments
Wind Slab	N E S W	Isolated Specific Widespread	Unreactive Stubborn Reactive Touchy

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