Observation: Mineral Basin

Observation Date
03/4/2018
Observer Name
B

Region:

Location Name or Route
Lower Mineral Basin
Weather
Sky
Obscured
Precipitation
Moderate Snowfall
Wind Direction
Northwest
Wind Speed
Moderate
Weather Comments
Heavy snowfall in the early am through mid morning with S3 rates. Snowfall rates decreased by late afternoon and the winds accelerated with strong gusts occuring around 1600 and on. Transport was at least in the moderate range. Tempertures were mid winter like and appeared to never get above the low teens above 9500.
Snow Characteristics
New Snow Depth
15"
New Snow Density
Low
Snow Surface Conditions
Powder
Wind Crust
Snow Characteristics Comments

Excellent low and moderate angled riding, fast and fun. The snow appeared to be right side up and out of the exposed upper alpine, the conditions were very consistent and silky. Soft shallow wind slabs (4 finger) were observed from 9300 feet and above. It appeared that there most likely were areas of dense hard slab being developed in the most exposed upper alpine terrain, and especially on E, SE and S aspects. 

Red Flags
Red Flags
Heavy Snowfall
Wind Loading
Cracking
Poor Snowpack Structure
Red Flags Comments
Snow pits from 3/3/18 indicated a thin layer of small grained facets above the dirt layer that yesterday was 35 cm down. Several other mid pack weak layers and moderate sized basal facets were also observed 20 cm up from the ground. These basal facets were showing signs of rounding, but they were still generally uncohesive. See above for wind loading Minimal cracking was observed in the shallow wind slabs. Heavy PI rates were sustained from 1200 midnight throuhg at least 1600, and there appeared to be a reactive density break in the new snow 18 cm down, and widespread sensitive long running loose snow avalanches were observed.
Avalanche Problem #1
Type
Loose Dry Snow
Trend
Same
Problem #1 Comments

See above for details on loose dry. 

Minimal soft slab avalanches were reported and or observed. 

 

Avalanche Problem #2
Type
Wind Slab
Trend
Increasing Danger
Problem #2 Comments

See above for details; and with the forecast for the winds to ramp up overnight, this potential and severity of this problem should increase over the next 24 hours. 

Continued reports from the outlying areas appear to indicate a strong likelihood for persistent slab potential with slides now ranging over the 1 meter threshold. 

Considerable in the alpine where wind loading was strongest appeared to be the appropriate high end danger rating for today, yet the majority of the terrain was moderate with loose dry avalanches and manageable soft storm slabs the issue.

Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable
Snow Profile Coordinates