3/13/2011 2:35:00 PM
by Meadows Team
in Connection, Media Center, Trails Blog
| 35 comments
This account and pictures of the avalanche investigation is provided by Tighe Stoyanoff and Paul Klein of our ski patrol. You can click on the pictures to make them larger.
A pronounced fracture line runs across the top of Super Bowl - unlike the January 2010 major incident which started in Wy' East (which is still loaded with snow and presumably has the same persistent weak layering which contributed to the March 2011 Super Bowl slide).
Thursday's Investigation
On the morning of March 10th 2011, the Mt. Hood Meadows Professional Patrol conducted Avalanche Hazard Reduction routes and an Artillery mission that included the Super Bowl portion of the permit area. Weather conditions on the morning of the 10th did not allow for any visibility into the upper portions of the Heather or Clark drainages. The Heather Ridge route traveling through the Heather Canyon foothills on the tail end of their route found the deposition from a large avalanche at the confluence of the Clark and Heather Drainages. At that time visibility up drainage did not allow for confirmation of where this large event had initiated from. Debris extended past the bottom terminal of the Heather Chairlift, making travel difficult on skis or foot. The canyon remained closed for the day.
Friday's Investigation
As the sun came up on Friday the 11th, the weather forecast held true and visibility allowed for further Avalanche Hazard Reduction and investigation into the previous days events. Patrol personnel traveled to the fracture line of the avalanche at the 9000 foot level, very close to the top of our permit area. It was determined that the avalanche was triggered during our Artillery mission on the morning of the 10th just after 6:00 am. The slide ran on an old buried and persistent weak layer. Average height of the fracture was 5-6 feet with areas in excess of 12 feet. The hard slab traveled an estimated 3900 feet of vertical and 2.5 miles as the crow flies. Wy’east, the slope directly up hill of Super Bowl did not slide. It is presumed that Wy’east has the same persistent weak layer and similar loading that contributed to the slide at the 9000’ level in Super Bowl. The canyon remained closed for the day.
Saturday Open for "Touring"
Saturday the weather, snow pack, and some grooming near the bottom of the chair allowed Heather Canyon to open for a short time from 9:00 am to 11:00 am. Absolute Magnitude was the only gate open which allowed Patrol to better inform guests of the debris hazards and difficulty of access to the chair. Weather closed in again just before 11:00 am, causing increased concern for the Wy’east Face; resulting in the Canyon’s closure. Wy’east is outside of the Meadows permit area and receives no active Avalanche Hazard Reduction. Historically slides originating from Wy’east face have deposited debris in the lower portions of the Clark Creek drainage. Pictures speak more than these words in describing the magnitude of this slide and the challenges we face with this terrain.
Please obey all posted signs and closures. Heather will continue to be evaluated, at the time of this posting it is closed.
The mountain is the owner, we are but guests…………..