| Recent Avalanches? | No |
| Collapsing (Whumphing)? | No |
| Cracking (Shooting cracks)? | Yes |
Observation: Summit
Location: Fresno Ridge
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.
Obvious signs of instability
Observer Comments
Small isolated "pizza box" wind slabs were cracking under our skis from ~2000' and above (see photos).
Weather
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).
Snowpack
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.
Pit Profile 2640', SSW Aspect, 22* Slope, HS = 65 cm. CT14SC, ECTP24 down 55 on 3mm depth hoar.
Puffy new snow on vegetation at 2500': Indicative that new snow has fallen under calm winds.
Ski pen at 1100'. 2" of new snow on a breakable crust.
Breakable crust at 1100'. Note the translucent rain crust.
Conditions on the west side of the highway remain thin, variable, and challenging at lower elevations.
"Pizza box" wind slabs at 2000'.
Buried surface hoar immediately below the new snow at 2500'.
Hand pit at 2500'. The block failed on isolation on the facets below the crust nearest the surface. Surface hoar, pictured above, was found intact in this pit.
Pit Profile 2700', S Aspect, 29* Slope, HS=130cm. CT17, CT15, ECTN15 down 25cm below melt-freeze crust.
Crust at 1700'. Note facets attached to the top and bottom of crust.