Observation Date
2/21/2025
Observer Name
Zimmerman-Wall
Region
Salt Lake » Big Cottonwood Canyon » Mill D North
Location Name or Route
Mill D North- Mountain Mahogany
Weather
Sky
Clear
Wind Direction
North
Wind Speed
Light
Weather Comments
Tour from Spruces starting 0900. Stunner. High above the valley stratus and winds were nearly non-existent. Some light transport around 10am noted off of Clayton at the head of the BCC drainage. Temps were steady rising. 18F in the parking lot to start, 34F by the time of departure at 1200.
Snow Characteristics
New Snow Depth
8"
New Snow Density
Low
Snow Surface Conditions
Powder
Damp
Snow Characteristics Comments
Excellent surface conditions. New snow was rightside up with surface hoar growth on all aspects travelled up to 9200'. South facing structure is quite consistent. Surfacehoar atop 20cm of new snow, with increasing hardness down to prior storm at 20-40cm. Graupel noted from 40-50cm, bonding well to only notable crust (2cm thick) down 60-80 cm. Sitting on large grain facets just above ground. Overall HS was 80-120cm from 7500-9200' on Mountain Mahogany ridge heading up to the top of Short Swing. By 11am it was starting to warm considerably. Roller balls and minor sluffing on slopes >35 degrees.
Red Flags
Red Flags
Recent Avalanches
Rapid Warming
Red Flags Comments
Noted small Dry and Wet Loose avalanches today.
Avalanche Problem #1
Problem
New Snow
Trend
Same
Problem #1 Comments
Alexander Basin had evidence of recent Dry Loose avalanches on East and South facing above 9'000. Similar evidence noted on North Superior. No slab avalanches noted in upper Days, Cardiff, or off of Kessler. On the road cuts heading down canyon below below 8,000' there were numerous Wet Loose avalanches with some piles reaching the white line.
Avalanche Problem #2
Problem
Persistent Weak Layer
Trend
Same
Problem #2 Comments
Did not dig to observe this problem today. However, old crowns on Raymound, Reynolds, and upper Days were visible under the new snow. We know this problem is there, and we will have to continue to be patient. The concept of Impermance is worth exploring during times like these...
Comments
Photos:
1. Surface Hoar at 8000' ridge.
2. Alexander Basin Dry Loose
3. Stratus clouds of Mill Creek and Beyond.
4. Mid BCC road cut Wet Loose
5. Lower BCC stratus draped on Storm Mountain.
Of note, a moose was bedded down on the shoulder of Mountain Mahogany. I accidently disturbed it on my exit and it bolted on to a stepper slope without any observed avalanche activity beyond pinwheels. Be mindful if you find yourself in the area.
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
None
Coordinates
