Propagation at Upper Elevations on Red Lake Peak

Location Name: 
Red Lake Peak
Carson Pass Area
Date and time of observation: 
Thu, 12/04/2014 - 13:45
Location Map: 
United States
38° 43' 0.408" N, 119° 58' 57.648" W

Red Flags: 
Recent loading by new snow, wind, or rain

Observation made by: Forecaster
Snowpit Observations
More detailed information about the snowpack: 

Mostly rain fell on the lower elevations of Red Lake Peak and only a few inches of snow cover existed until about the 8000 ft. elevation. Between 8000 and 9000 ft. the snowpack measured between one and three feet in depth and consisted of mostly new snow on top of thin old snow layers. At these elevations the old weak layers at the base of the snowpack had become moist and had started bonding similar to the conditions seen on Castle Peak yesterday. Above 9000 ft. the snowpack measured between three and four feet in depth in non-wind-loaded areas. The old facets at the base of the snowpack became less cohesive and remained loose, weak, and dry. The snowpit and video come from a NE facing slope at 9700 ft. Snowpit tests here revealed that if the weak layer at the base of the snowpack breaks, the resulting crack can travel through that layer. At these upper elevations, snowpit tests also indicated that fractures could travel along a graupel layer buried about one foot deep. Hand pits, probing, and quick shovel pits only revealed the old facet layers on the NW-N-NE aspects (places that held snow during the fall).

Cornices above wind-loaded test slopes above 8700 ft. broke easily when weighted, but those wind-loaded test slopes did not fracture when the oven-sized cornice pieces fell onto them. Ski cuts also did not produce any results on wind-loaded test slopes between 8700 and 9700 ft.

Video: Fracture traveling through the basal facets during a propagation saw test on a NE aspect @ 9700 ft.

Snowpit or crown profile photo or graph: 
Snowpit videos (tests, etc): 

Fracture Propagation through Facets on Red Lake Peak

Weather Observations
Blowing Snow: 
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

Snow squalls followed by small breaks in the clouds occurred throughout the day.