Pro Field Report

Basic Information

Observation Details

Observation Date:
April 6, 2023
Submitted:
April 7, 2023
Observer:
SAC - VandenBos (off duty)
Zone or Region:
Sawtooth and Western Smoky Mtns
Location:
Fishhook (6,500-9,800, all aspects)

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
Isolated
Collapsing? 
None Experienced
Minor, isolated cracking in fresh wind board.

Media/Attachments

Large cornices are beginning to peel away from the ridges they cling to during periods of warm temperatures. Give these beasts a wide berth when you are traveling on ridges, and be alert to the ones that are hanging above you. Failing cornices are dangerous on their own and can also be very effective triggers for deeper weak layers in the snowpack.
This loose snow avalanche released naturally under the sun's influence in the Sawtooths. Though small, slides like this can knock you off your feet and carry you through ugly terrain.
This slab avalanche failed during the heat of the day. It likely failed on a crust+facet combination. This slope faces SE at 8,800'.
This slab avalanche failed during the heat of the day. It likely failed on a crust+facet combination. This slope faces SE at 8,800'.
Widespread wet loose avalanches were observed in the Sawtooth Mountains on Thursday, April 6. There is still a lot of dry snow that will be coming down off the mountains in the coming days.

Advanced Information

Weather Summary

Mostly clear skies at sunrise with some slow-moving clouds passing through. Cloud cover built for a few hours in the afternoon, though sky cover was never more than 50-60%. Skies cleared into the late afternoon and were clear at sunrise. Temps felt warm in the sun, but seasonably cool in the shade. Winds were calm to light during the day, picking up to moderate speeds from the south as I exited along the morraine.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Photos Details
10 Apr 6, 2023
(Exact) 		Fishhook
S 9000ft 		D1 WL-Wet Loose N-Natural
Widespread wet loose avalanches were observed in the Sawtooth Mountains on Thursday, April 6. There is still a lot of dry snow that will be coming down off the mountains in the coming days.
Report
Fishhook

I observed a widespread wet loose avalanche cycle today. During the mid-morning and early afternoon, when sun was unobstructed by clouds, I was hearing natural loose avalanches every few minutes, sometimes more than one at a tie. Many of these were small, but some were approaching D2 in size. The starting zones of the larger avalanches had some crowns visible. I think the changing slab properties from the sun in combination with the touchy MFcr+FC weak layer were enough to produce these slabs. The largest slab I observed broke an estimated 400+ feet wide.

Snowpack Observations

The snowpack took a lot of shortwave and longwave radiation today. Any slope that tilts towards the sun got a crust, and many flat and even slightly shaded slopes at low and middle elevations were undergoing some melting at the surface. As I exited the field at the end of the day, SW-W facing slopes that visible water in the upper 2 cm of the snowpack, producing some excellent glopping conditions. I dug in two locations looking for persistent slab problems on shaded slopes. There are a few non-descript interfaces consisting of small facets sandwiched between dense snow in the upper few feet of the snowpack. These produced ECTNs and ECTXs and generally rough, dirty shears. I'm still a bit leary of these and chose not to expose myself to large, open, steep slopes where this combination existed.

Avalanche Problems

Persistent slabs and wet issues drove my terrain selection today.

Terrain Use

I very selectively entered some avalanche terrain. I am still avoiding most avalanche terrain.