Observation: Public
Observation Details
Name:
Ian CulhaneObservation Date:
May 30, 2021Submitted:
May 31, 2021Zone or Region:
OtherActivity:
Skiing/SnowboardingLocation:
North Sister (Oregon)Triggered Avalanches
Did you trigger any avalanches?
YesWas it intentional?
NoAvalanche Type:
Wet SlabSize:
Size 2: Could bury, injure, or kill a personElevation:
9050'Aspect:
SComments:
Two slides. 3-6" crown (primarily 3"), total crown width of ~250', slide length of ~800'Photo:
Signs of Unstable Snow
Did you see shooting cracks?
NoDid you experience collapsing or whumpfing?
Yes, IsolatedObservations
Set off two wet slides skiing down North Sister at ~2pm via the standard south route. First slide was remotely triggered from about 40' above, had a crown width of ~100', and slid for ~500' before stopping on slightly more mellow terrain. Second slide broke at ski tips while traversing skiers right towards exposed rocky ridge - crown width of ~150' and total slide length of ~800'. It appears that the staunch wall for both slides was ~100' below the crown. Below this both were more wet loose in nature, and took several minutes to slow to a stop. No skiers were caught in either slide.
Weather: Saturday and Sunday were hot and sunny. Temperatures were below freezing overnight.
Snow conditions: Both slides presumably occurred on the interface between the old snowpack and the several inches of fresh snow forecasted for the 27th-28th. Isolated whumphing/collapse was observed the previous day between 8000' and 9000'. Small rollerballs were observed on steeper aspects but did not gain in size.
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