Observation: Upper Collins area

Observation Date
10/26/2019
Observer Name
Peter Donner
Region
Salt Lake » Little Cottonwood Canyon » Alta Ski Area » Upper Collins area
Location Name or Route
Alta Collins Gulch
Red Flags
Red Flags
Poor Snowpack Structure
Comments
First, again and always thanks to Alta for allowing uphill traffic. The resort is beginning prep work for opening and staff are on the mountain working. Snowmobiles in particular are moving across terrain and the uphill community needs to be mindful of their presence so they can get their work done.
Toured Collins Gulch the past 5 days. Warm days and cold nights have made for bone rattling starts on melt freeze crust and soft corn-like carving in the afternoon. Friday and Saturday the day-time high at Goldminers was 50 degrees, though the pre-frontal winds Saturday made it feel a bit cooler. Isolated a bunch of columns Staturday with a common feature of melt-freeze/wind crust at least an inch thick. Upper Ballroom under the Baldy cliffs at 10,300 feet had pencil hard wind board 6 inches thick. Lower in Collins Gulch was less wind affected. Snowpack under the crust varies from loose to the ground to dense with clean shear on the 10/18 layer. In one spot the 10/18 layer is difficult to identify, 20 feet away it is an obvious failure plane. Bottom line is a shallow, varied and weak snowpack that will not support a significant load. Overall avalanche hazard the past few days seems low; the hazard from hitting rocks and logs is high.
Winds were gusting Saturday afternoon moving a bit of snow on Baldy. The Germ pass station reported gusts in the 30s all day.
NWS forecast for upper Collins is one-half inch overnight with winds gusting to 16 mph, 2 inches during the day Sunday with winds gusting to 15 mph. The U's LCC guidance has winds on Baldy gusting to 50 mph overnight, with a few inches possible. The U's short range ensemble forecast for upper Collins, comprised of 24 members, averages about and inch with two members at 5 inches, many at 0, and the rest less than 3 inches.
Assuming little snow with strong gusts on Baldy, calmer winds in the more sheltered terrain of Collins Gulch, the hazard from avalanches seems like it will be mostly low Sunday. Given the winds, avalanches in places like Main Chute of Baldy or Jaws of Days Fork seem possible Sunday. Avalanches in less radical terrain seem unlikely. Forecast of moderate is for the most radical terrain.
Today's Observed Danger Rating
Low
Tomorrows Estimated Danger Rating
Moderate