Observation: Seward

Location: Mt. Eva

Route & General Observations

We toured up Mt. Eva to check out snowpack conditions after the storm on Sunday and the wind event on Tuesday. We were surprised to only see one avalanche that seemed to be related to the wind event. Unfortunately, we did see a glide avalanche on the south face of Mt. Eva. There were also a few glide cracks opening up toward the bottom of the south facing couloirs on Mt. Eva. I was hoping this glide problem was going to stay north of the Seward zone, but these observations are showing this problem is “creeping” south. There was some soft snow above treeline, but we had to hunt for it as the wind had affected many places.



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

We saw one large avalanche on a south facing slope on a mountain north of Mt. Ascension. We had very good visibility and this was the only avalanche we saw that seemed to be related to the wind. I jumped on a test slope and got a small shooting crack, but was not able to produce an avalanche.

I saw a glide avalanche on the south face of Mt. Eva. This is the furthest south I have observed a glide avalanche. Prior to this I had hoped this problem only existed as far south as Wrong Mountain in the Carter Lake area. There were also a few glide cracks on the south facing couloirs of Mt. Eva, see photo.

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

It was a pleasant day with temperatures around 20 degrees F, broken skies, light north breeze, and no precipitation.

Snow surface

There was a very stout crust/series of crusts at 300’ with some surface hoar on top. At 700’ there was a few inches of snow on top of the crust and by 1,200’ the crust was gone and the snow was very deep. I did not observe surface hoar above the valley floor. Above treeline there was a wind layer that varies in thickness and was breakable in places and supportable in others.


We dug a pit at 2,000’ on a southwest aspect. The wind slab did fail easily in compression but wasn’t clean and didn’t appear to have much energy or propagation potential in this location (CT3 RP, ECTN 12 - 9cm down on the interface of the wind slab and storm snow. CT27 RP, ECTN27 - 29cm down on a slight hardness change F to F+). There was a 4” (9cm) wind slab on top of decomposing new snow and an otherwise right side up snowpack. There was a .5cm thick rain crust (not the Thanksgiving crust, that was deeper) 101cm down with some faceting rounds below it, but we did not get any results on this layer. The Thanksgiving crust was at the bottom of the pit and I didn’t dig below.

Photos & Video
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