** IMPORTANT ANNOUNCEMENT **

As of March 30th, COAC has suspended backcountry avalanche advisories and pro observations until further notice.

On March 23rd, Governor Brown of Oregon issued Stay at Home orders for the public regarding the COVID-19 outbreak. The directives are clear in that “to the maximum extent possible, individuals stay at home or in their place of residence.” On March 27th the Deschutes National Forest issued a closure of all developed recreation sites including trailheads and snoparks. COAC is committed to supporting our community, local emergency services, and agency partners and because of this we felt it important to cease operations as we all work together to minimize the impacts and spread of COVID-19.   

This decision was not taken lightly. Aside from the need to maintain congruency with the Governors' orders, there are inherent risks with backcountry activities in alpine environments and it’s important to consider unnecessary exposure to COAC forecasters, first responders, and local medical staff in light of the current situation.

We look forward to getting back into the mountains and providing you all with the tools to recreate safely in the backcountry. Until then we thank you for your continued support and wish all our mountain community the best of health and wellness.

Alpine conditions

Location Name
North Sister
Region
Three Sisters Area
Name
Kevin Grove
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I would like this observation to be published on the site
Position
COAC Observer
Date and time of avalanche (best estimate if unknown)
Red Flags
Recent avalanche activity
Avalanche Type
Slab
Trigger type
Natural
Slope
45degrees
Aspect
Northeast
Elevation
8000ft.
Crown Height
1 ft
More detailed information about the weather

 The air temp was 2c and snow temp was -3c.  Skies were overcast and winds started calm but grew stronger around 11am before calmiing again.

More detailed information about the avalanche

 I toured into North Sister today to check out the conditions in the high alpine.  The road is clear to the pole creek TH.  We hiked on dirt and firm snow for 30 minutes before starting to skin.  The snow was frozen melt-freeze crust that totally supported our weight of skis and boots to 7000ft.  Approaching the NE face, just above treeline, my partner noticed a crown in the Early Morning Couloir (see photo).  It appeared to be a 1-2ft natural release and quite sizable.  We continued to tour over to the east face and approaced a SE facing slope low on the east buttress.  Initially at 7500ft we encountered 2 inches of wind slab over the top of two small rain crusts that sat on 12 inches of low density (4F) snow on top of a firm ice layer.  Further up the slope and approaching more of a gully we found a deeper snow pack up to 3 feet above the ice layer consisting of the same shallow wind slab, ice layers, 4F snow, then a very thin ice layer on top of 1F snow transitioning to pencil hardness about 1 foot above the ice layer.The top wind slab and ice layers failed very easilty on both hand shear and compression test.  Another moderate failure occured on the compression test at the very thin ice layer lower down.Be safe out there.Kevin