Northern Madison

We rode out Buck Ridge, through Second Yellow Mule, around the top of Third Yellow Mule, and through the top of McAtee. Snowed average S1 all day until 2pm when we rode out, and was still snowing up high at that time. Wind was light from the north. Minimal drifting and transport in the morning, but some very shallow, very soft slabs cracked on wind-loaded slopes near the ridge. Avalanche activity was limited to very small F- dry loose and some F- 2-4" soft slabs. Visibility was not great though. Natural and triggered by us on small test rolls.

There was 4" of new snow on average, and up to 8" of low density snow in places. Below today's snow there was 1-2" of snow from earlier in the week, and that was on top of a layer of surface hoar in some places or soft facets in most places.

The primary concern was and will be where the recent snow gets drifted into thicker or stiffer slabs. Recently buried weak layers might make these fresh wind slabs easy to trigger initially, and possible to trigger for longer into next week. Where today's new snow was not drifted there was minimal hazard aside from small dry loose avalanches.

We dug on an E facing slope at 9,400'. HS was 155cm and we had an ECTN12 on the surface hoar layer at 130cm above the ground.

From email: "Skies were clear at 8am, but clouds rolled in quickly and we had S-1 snowfall starting at 1pm. Winds were L in the basin and L-M at ridge tops out of the W-NW. Moderate snow transport on high elevation peaks. West aspects near ridgetops were scoured, as they usually are. We found a 2-3cm thick MF crust under 5-10cm of new snow on E, W, and S aspects near ridgetops and in the basin. No cr, co.

Students dug pits on E-SE aspects at 9200', as well as on E and W aspects near the Prayer Flags. HS ranged from 100-145cm. Two of ten pits had propagation. ECTP1 on small facets above the MF crust and under a wind slab. ECTP30 on 2mm facets 30cm up from the ground. Hand pits had planar results below the MF crust where it was capped by a wind slab." 

Aspect: East

Elevation: ~9000ft

Snow Depth: 155cm

Pit:

• 155-20cm 1F
• 20-0cm 4F/Fist
• ICT7 (Thin Crust layer at 135cm)
• ECTX

Snow:

• Wind affect up higher. Stayed out of bowl as our chief concern was triggering a wind slab loaded on the crust layer at 135cm. Did have shooting cracks at the top wind affected area. Great snow otherwise!

Dug a pit on divide peak on a southwest facing aspect that was about 210cm deep. ECTX, PSTX on sun crust 15cm down from surface that the new snow had fallen on. Entire snowpack 4F-1F from the thin sun crust to the buried facet layer than began around 165cm deep. Saw evidence of some wind slabs beginning to form near the ridge line. It was cold. 

Skied a few laps above Deer Creek today, E through SE aspects between 7000' and 8250'

Only about an inch of new snow in past 24 hours

Calm to light winds from E; blowing and drifting snow filling the skin track on isolated, wind-exposed terrain features above 7400'

No recent avalanches, whumphing, or shooting cracks observed

Average ski penetration 15-20 cm above 7000'

Dug a test pit on an E aspect at 8200'; HS 110 cm

ECTN 28 down 25 cm from top

Pit showed poor snowpack structure (30 cm of F-hard, 2mm facets at base) with 1F-hard slab sitting above. We were unable to affect the facet layer with our ECT and we were too cold to do a PST! A little extra force after the ECT did get a sudden collapse at the ground. 

Large wind transport in Spanish peaks. Photo: T Blakeway

Large wind transport in Spanish peaks