Avalanche: Hatcher Pass

Location: Cable Valley/ Microdot

Route & General Observations

Toured from Independence Mine Lot towards Cable Valley, breaking trail in 9-10 inches of new snow. My intent was to look for recent avalanches and persistent weak layers underneath the new snow from this week. I saw evidence of numerous small loose dry avalanches and a storm slab avalanches in Eldorado Bowl. Upon my exit from Cable Valley at 3:35pm I witnessed a skier triggered soft slab avalanche that sympathetically released two other avalanches on the lower west/northwest slope of Microdot.

Avalanche Details
If this is an avalanche observation, click yes below and fill in the form as best as you can. If people were involved, please provide details.
Trigger SkierRemote Trigger No
Avalanche Type Soft SlabAspect West Northwest
Elevation 4200ftSlope Angle 39deg
Crown Depth 18inWidth 300ft
Vertical Run 250ft  
Avalanche Details

At 3:35pm a single skier and their dog were descending the lower west/northwest aspect of Microdot when they triggered a soft slab avalanche. The skier was 2/3 of the way down the slope when the avalanche broke above them and sympathetically released two other adjacent pockets of snow. The skier was not caught nor carried and managed to ski in front of the advancing debris away from the runout of the slide. They noticed the avalanche was coming at them 3/4 of the way down as they turned to look for their dog. The skiers dog came down after the avalanches had stopped and was uninvolved. The skier said as they increased slope angle upon descent the avalanche began to initially slide on or just below an old slick bed-surface. The skier was on their third lap of the day with two successful runs down the backside of Microdot from the upper saddle. Ear-buds prevented them from hearing the sudden collapse or whumphing sounds.
Moments earlier I dug a snowpit on a similar aspect and elevation and assessed the persistent weak snow grains below this older crust layer and found them to be dry unconsolidated facets. The breakable slick crust was decomposing but still pencil hard with small irregular facets beneath. Around 33 inches of recent snow since 3/31 was sitting atop this melt-freeze crust adding 2.8 inches of snow-water equivalent. This mass of snow and its weight, coupled with poor snowpack structure, a little sun, and a human trigger were the right recipe for avalanches in this location.

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)?Yes
Cracking (Shooting cracks)?Yes
Observer Comments

Initially during my morning tour the only signs of instability were numerous loose dry avalanches in steep terrain on all aspects. Until I witnessed the human triggered avalanches I did not experience whumphing or see cracking in the new snow, but I kept my slope angles below 35 degrees. The witnessing of human triggered avalanches is bulls-eye evidence that both cracking and collapsing were possible.

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

Thick valley clouds up to 3000 feet which advanced up to 4000 feet around 3pm. Sun was warming the surface of the new snow above these clouds to a depth of 2 inches. The temperature was 23F degrees with calm winds.

Snow surface

Height of new snow was 9-10 inches in the last 24 hours. The surface was soft with new precipitation particles that were unaffected by the wind. Numerous small loose dry avalanches were visible on terrain that was steeper than 35 degrees, on all aspects. Direct sun and green-housing below light clouds caused some melting of the surface snow making it sticky.


I dug numerous quick pits on different aspects. I dug a focused pit on a northeast aspect at 4150 feet just below the "Death Traverse" which is graphed with snowpilot and illustrated in a photograph. I had three test results that showed moderate instability at the interface below the Easter Storm ECTN13@255; CT11@255 PC; and CT13@255 PC.
On aspects which face southwest through northwest I was finding a pencil hard crust below this weeks 33 inches of snow that had loose facetted grains below.

Photos & Video
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