Ad
The National Forest Service Logo
icon-add Observation
Forecasts
Logan Ogden Salt Lake Provo Uintas Skyline Moab Abajos Weather Archives How to read the forecast
Observations & Avalanches
Submit Observation Observations Explorer All Observations Avalanches Fatalities Weather Place Names Map Archives
Education
Avalanche Class List UAC Class List Online Classes Resources and Tutorials Avalanche Awareness Develop Skills
Events
Store
About
Contact Who we are Core Values Staff Board of Directors Past Forecasters Sponsors Annual Reports Sign In
Blog
icon-add Observation
Donate / Join

Observation: Flagstaff Ridge

Observation Date
12/17/2015
Observer Name
Tyler Falk
Region
Salt Lake » Little Cottonwood Canyon » Flagstaff Ridge
Location Name or Route
Flagstaff
Weather
Sky
Clear
Wind Direction
West
Wind Speed
Moderate
Weather Comments
Clear and cold in the Morning high clouds came in mid morning making it overcast in the afternoon.
Snow Characteristics
New Snow Depth
12"
New Snow Density
Low
Snow Surface Conditions
Powder
Snow Characteristics Comments

About a foot of new in LCC overnight. Lots of terrain saw some amount of wind damage.

Red Flags
Red Flags
Recent Avalanches
Heavy Snowfall
Wind Loading
Cracking
Collapsing
Poor Snowpack Structure
Red Flags Comments
Lots of red flags out there.
Avalanche Problem #1
Problem
Wind Drifted Snow
Trend
Decreasing Danger
Problem #1 Comments

Lots of windslabs out there today on almost all aspects. The most active seamed to be on east aspects from the NW winds that blew up to 80 mph as Evelyn said on the early morning advisory.

Avalanche Problem #2
Problem
Persistent Weak Layer
Trend
Same
Problem #2 Comments

These are definitely going to be large slides in the unmanageable category.

Wow what a storm!! Almost four feet of new snow in upper LCC. From Tuesday afternoon to this am there is around 55 cm of added depth to the snowpack at 9k in the same location. Up to 125 cm HS from 70 cm on Tuesday at 9k. Saw a few Artillery triggered slides this am from UDOT. The two I saw had a east component to them. (The one on superior and Toledo chute) The largest collapse I felt all day also occurred on a east aspect. (See pic below) Some cracking noticed around turns when we pushed the angle a bit. Did one quick ECT on a SE aspect around 9400. About the same results from a similar aspect that had a bit higher elevation from Tuesday. ECTP 17 Resistant Planar on 2-3mm facets below the storm snow that was 65 cm down from he top of the pack in that location.

Pic 1 Snow transport around Cardiff pass

Pic 2 Facets on east aspect on the ground where ECT failed. (3mm grid)

Pic 3 Cracking around turn

Pic 4 Artillery triggered slide in Toledo chute

Pic 5 Collapse with the snow pulled away. Failed on facets near gound.

Today's Observed Danger Rating
High
Tomorrows Estimated Danger Rating
Considerable