Observation: Chugach State Park

Location: Far North Bicentennial Park, Anchorage, Hillside Mountain Bike Trail: Jeff's Whoop-Whoop (61° 8' 20.58" N, 149° 44' 35.78" W)

Date:
Observer:
Route & General Observations

Yesterday while conducting a work-related trail inspection on the newly opened Anchorage Hillside mountain bike trail called “Jeff’s Whoop-Whoop”, we observed several trail side-slopes (cut banks) with potential small avalanche hazard. The image attached was just one example to warrant an observation, but other situations did exist along the trail. My concern was that these trails are new and winter bikers may not be aware of the potential for avalanches.

Observed: (see image)
Side slope of trail with steep cut-bank (height ranging from 5′ to 15′ tall), potential for small slides.
Slope angle of side slope: 30 +/- degrees
Observations: new snow layer (4”-6”) on top of a rain crust with a 2″+/- layer of facets on bottom.
Why concern? These conditions are new to Hillside winter bikers. Fat Bikers were observed riding the new trails, packing them down and the side slopes are being undercut creating a weakness in the snowpack. This was observed on several of the newly cut trail side slopes. I think it is of little to no danger now given current conditions, but could become one if we see more snow or a temperature change. Several small sloughing slides were observed along other banks on this trail.
Image Map Link: https://www.pic2map.com/xncahl.html

Red Flags
Red flags are simple visual clues that are a sign of potential avalanche danger. Please record any sign of red flags below.
Obvious signs of instability
Recent Avalanches?Yes
Collapsing (Whumphing)?No
Cracking (Shooting cracks)?Yes
Observer Comments

Sloughing, small cut-bank side slope slides and cracking along other side slopes were observed where cut-banks were steeper and the trail was compacted.

Weather & Snow Characteristics
Please provide details to help us determine the weather and snowpack during the time this observation took place.
Weather

snowing, 4-6" new snow, no wind, temp about 25 degrees +/-

Snow surface

New snow, 4-6" on top of a thin rain crust layer

Snowpack

New snow was starting to condense, noticed moisture in new layer; thin (2-3cm ice layer likely from recent rain event); 2" +/- of facets on bottom.

Photos & Video
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