Observation: Summit

Location: Fresno Ridge

Route & General Observations

Toured up Fresno Ridge to ~2700′. Objectives were to inventory surface conditions and investigate the distribution and reactivity of various persistent weak layers. We were also on the lookout for recently formed wind slabs.

Red Flags
Red flags are simple visual clues that are a sign of potential avalanche danger. Please record any sign of red flags below.
Obvious signs of instability
Recent Avalanches?No
Collapsing (Whumphing)?No
Cracking (Shooting cracks)?Yes
Observer Comments

Small isolated "pizza box" wind slabs were cracking under our skis from ~2000' and above (see photos).

Weather & Snow Characteristics
Please provide details to help us determine the weather and snowpack during the time this observation took place.

1000: Mile 49 gravel pit, 1100', 3*F, calm wind, snowing lightly
1230: 2700', temperature not measured (cold!), calm wind, snowing 1/2" per hour
1400: Mile 49 gravel pit, 1100', 4*F, calm wind, snowing lightly

Puffy new snow on vegetation above 2500' indicated that recent snowfall has not been accompanied by much wind.

Snow surface

~2" of new snow (last 24 hours) and ~1/2" to 1" of near surface facets sits on a breakable melt-freeze crust. Below the melt-freeze crust are 3-4" of older near surface facets below 2200'. Above 2200', the melt-freeze crust gets substantially thinner and weaker, and there are 5-6" of snow above it. The melt-freeze crust was still present near the surface at 2640'. Buried surface hoar was found below the most recent snow (see photos).


The snowpack is generally thin, and highly spatially variable. At all elevations we travelled below treeline, weak snow is near the surface, sitting on various crust / facet sandwiches in the midpack. In a previously wind loaded location at treeline, a thicker, hard slab was found sitting on multiple buried surface hoar layers. Well developed cupped, striated 3mm depth hoar can be found at the base of the snowpack, sitting below a stout 4-5" thick melt-freeze crust.

We dug two pits at 2640':

Pit 1: SSW Aspect, 22* slope, HS=65cm. ECTN14 down 17 on facets below a melt-freeze crust, CT14SC down 55 on 3mm depth hoar, ECTP24 down 55 on 3mm depth hoar.

Pit 2: S Aspect, 29* slope, HS=130cm. CT17, CT15, ECTN15 down 25 below a melt-freeze crust at a density change.

Photos & Video
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