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Observation: Flagstaff Ridge

Observation Date
1/22/2019
Observer Name
Wilson, Hardesty
Region
Salt Lake » Little Cottonwood Canyon » Flagstaff Ridge
Location Name or Route
Cardiff, Flagstaff
Weather
Weather Comments
Cold temps, calm winds and no snow transport noted. Toured from 1100 to 1730 and skies alternate between clear and obscured in a low cloud bank.
Snow Characteristics
New Snow Depth
19"
New Snow Density
Medium
Snow Surface Conditions
Powder
Wind Crust
Snow Characteristics Comments
Right side up storm, with the final few inches light and feathery.
Red Flags
Red Flags
Recent Avalanches
Heavy Snowfall
Wind Loading
Red Flags Comments
Evidence of widespread cycle during the storm, with crowns in Cardiac, Toledo Chutes, Holy Toledo and elsewhere. All presumably in new snow. Plenty of newer sluffs visible, with the only deeper crown a north west aspect above 10k. Wind effect was evident on north, east and west aspects in upper Big Cottonwood canyons, but the south slope into LCC was soft. Loading along ridgelines, but we didn't see evidence that wind slabs were sensitive. Didn't really get into terrain where we could say they were stubborn, either. A couple pertinent negatives from today: Dropped a cornice in Upper Days with no result, and saw a half-dozen tracks on Superior. Had wondered what direct sun on cold snow would do to south facing paths, but intermittent cloud-cover kept the slopes cool.
Comments
Below:
1. Much of Cardiac bowl/ridge had avalanched in the storm.
2. Toledo Chute slid. Two crater holes show where howitzer rounds had no results, but at the bottom of the photo you'll see carbon residue evident in debris from a different slide. Hats off to UDOT and ski area employees!
3. Plenty of wind effect in Upper Days Fork, but a cornice drop onto steep slope had no result.
4. Lots of sluffs like the ones shown here.
By late morning the sun had begun to impact ESE through South slopes. While the top 3cm stayed cool (cold temps, clear sky, very light snow), the insulated layer below warmed up and formed a thin crust and presumably radiation recrystalization facets as well. Hard to imagine this crust/facet combo would act as a weak layer under the 2-6" of snow forecast for the next few days, but figured I'd give it a mention.
Even with the forecasted 25-35 mph southwest winds, I think the hazard tomorrow will be on the moderate side of considerable.
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable
Coordinates