Observation: NWAC Forecaster

All Observations

Basic Information

Observation Date:

April 7, 2023

Submitted:

April 7, 2023

Observer:

NWAC Forecaster - Dallas Glass

Zone or Region:

West South

Location:

Crystal backcountry: Bullion Basin (All Aspects Near and Below Treeling (4300-6500ft))

Recent Avalanches?

Yes

Cracking?

Isolated

Collapsing?

None Experienced

Some rollerballs were more than 3 feet in diameter and 2 feet wide.

Convex test slopes produced shooting cracks like this failing at the base of the new snow.

Snow profiles in the Crystal backcountry showing the two most recent storm interfaces.

Piles of rollerballs like this indicate the snow surface is becoming wet and unstable.

Piles of rollerballs neat the rain-snow line.

Small natural loose wet avalanches near the rain-snow line. E, 5800ft.

Advanced Information

Cloud Cover:

Mostly Cloudy

Temperature:

34°F

Wind:

Light , S

New/Recent Snowfall:

Storm Snow (HST) 4-6 inches (10-15cm)

Warm and damp! It felt kind of muggy up in the mountains. Occasional moments of sunshine provided good visibility.

Avalanche Observation Comments:

While most slopes held piles of rollerballs there were also a few small loose wet slides from the past ~48hr. I didn't see anything bigger than a D1 in my limited tour.

The rain-snow line appeared to generally sit around 5800ft. Above that elevation, substantially more snow was found in the trees.

The snow surface was wet to about 6500ft. Numerous rollerballs were seen on nearly all steep slopes. Some of these rollerballs were very large (3-4ft diameter and 2ft wide). Even with all these signs of wet snow, the rain didn't seem to penetrate very far into the snowpack. Below the surface, the snowpack remained very cold, dry, and layered.

At higher elevations, 4-6 inches (10-15cm) of heavy snow was found over the 4/6 interface. While rather stubborn, the storm snow would fail in uptrack and small slope tests. However, no slab avalanches were observed or triggered.

Cornices were generally smaller than normal, but they showed signs of the recent warm wet weather. They sagged and drooped in a few places along ridgelines.

Problem	Location	Distribution	Sensitivity	Size	Comments
Wet Loose	N E S W	Isolated Specific Widespread	Unreactive Stubborn Reactive Touchy	D1 D1.5 D2 D2.5 D3 D3.5 D4 D4.5 D5
Storm Slab	N E S W	Isolated Specific Widespread	Unreactive Stubborn Reactive Touchy

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