Observation: Summit

Location: Fresno Ridge to 3500'

Date:

March 9, 2016 4:00pm

Observer:

H. Thamm Professional

Route & General Observations

We ascended the SE shoulder of Fresno Ridge to 3500′ just above the weather station. We did not see any obvious signs of instability, but saw evidence of avalanche activity on a NE aspect of Colorado Peak, which occurred during the last storm cycle (ending Feb.29) We found a facet/crust combo on a NE aspect of Fresno that was reactive in tests and had propagation potential. Decided not to ski this aspect after these results.

Red Flags

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Observer Comments

None observed

Weather & Snow Characteristics

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

Weather

Sunny
Calm winds from the North
Temps: mid to high 30's F in the sun, mid 20's F in shade
No Precip

Snow surface

SE aspects: 1-2" breakable sun crust w/ very small facets (.5mm) on surface (Radiation Recrystalization)
South aspects: crust more supportable and surface was moist during the heat of the day
NE aspects: 2-3" low density snow on firmer snow

Snowpack

2300' - SE aspect, HS=200cm, 28* slope - Found 3 melt/freeze layers within top 100cm, but didn't find any layers of concern. Snowpack in this area was high strength with no propagation potential. ECTN11, down 25cm on a density change

3300' - NE aspect, HS=157cm, 32* slope - Found a crust layer down 55cm with rounding facets below it. Pit revealed five lemons, Test results showed propagation potential with moderate force. ECTP13 SC, ECTP16 SC failed on facet/crust combo.

Shaded aspects are more appealing right now due to a sun crust on solar aspects. We were planning to ski this particular slope, but after discovering this layer and how reactive it was in our tests we decided to ski back down the SE ridge. Its possible that this layer was responsible for older avalanche that we saw on Colorado (see photo below) as it is the same aspect and elevation.

Photos & Video

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