Observation: Ogden Valley

Observation Date
Ogden » Ogden Valley
Location Name or Route
My garage (Roof Slide)
Wind Speed
Weather Comments
Looking at the Ogden airport temps, it was warmer yesterday, with daytime temps around 41-44F, then a dip to 27 degrees F at 8:20PM, with overnight temps around 35F.
Snow Characteristics
Snow Surface Conditions
Dense Loose
Melt-Freeze Crust
Snow Characteristics Comments
Melt crust about an inch thick on the bottom, some layers evident with dense slab behavior. The top layer and next layer down were cohesive enough to crack a bit further back in spots.
Red Flags
Red Flags
Heavy Snowfall
Rapid Warming
This was the largest natural roof-a-lanche I've seen from our garage. Elevation is 4175 ft. A few points I find surprising:
I trimmed back the garage roof cornice a few days ago, and as of yesterday it had not glided at all. There was almost no cornice overhang last night at 8PM, perhaps an inch.
A dip in temps below freezing around 8:20PM yesterday 1/18/2024.
The garage is not heated, although it is attached to the house. A nighttime natural release was surprising, although in hindsight, the warmth of the day on the 18th must have been a factor.
The debris shows that overnight, the roof snowpack glided about 2 feet before collapsing.
Deepest (localized) depostion around 20 inches. The ice layer could cause a concussion if anyone happened to be under it. There is more snow up there on the roof as well. We could see another equal sized roofalanche sometime soon.
In other years when we've had roofalanches like this, with significant lower elevation snowpack and a warming trend, there were some lower elevation slidepaths active around here. There are a couple small slide paths that are capable of hitting the Ogden Canyon road, and one slidepath that hits the hiking trail from Smokey Bear trailhead in Ogden Canyon, right down near the road about 100 yards from the parking lot. "Considerable" hazard below 7000' today, as in the Ogden forecast, is correct. Checking elevations the areas I am talking about in Ogden Canyon are as low as 4640', which is a bit lower than most of the east bench areas in Ogden. For example the Taylor Canyon trailhead parking is 4840'. With highs in the 40s today and tomorrow, with rain tomorrow, we could see those wet "toothpaste" consistency slides in the major slidepaths, particularly below the rain line, like the west Mt Allen area (Scary Larrys), Hells Canyon, and Coldwater. These slides can run futher than usual. If the rain-snow line gets to 7000' it will get into steeper terrain, over 35 degrees, in Scary Larrys area in particular.
Today's Observed Danger Rating
Tomorrows Estimated Danger Rating