| Trigger | Snowmachiner | Remote Trigger | Yes |
| Avalanche Type | Soft Slab | Aspect | Northwest |
| Elevation | 2300ft | Slope Angle | 32deg |
| Crown Depth | 3ft | Width | 300ft |
| Vertical Run | 500ft |
Avalanche: Turnagain
Location: Seattle Ridge
We rode up Seattle Ridge to check out the avalanche that was remotely triggered by a snowmachiner yesterday. We wanted to see if it failed within the storm snow or if there is a weak layer it failed on, and we found that it had failed on a layer of surface hoar that was buried last week. We also saw multiple avalanches that had failed during and right after last weekends storm, with big avalanches in Zero bowl as well as the front side of Seattle Ridge. The snow was soft and deep in the flats as well as up high where it was not wind affected.
After we got a look at the crown, we moved on down the ridge to do some repairs to the weather station. Wind speeds should be more reliable now after we replaced some parts on the anemometer.
Avalanche Details
We got up to the crown of an avalanche that was triggered remotely yesterday. The avalanche had failed on a layer of buried surface hoar, and parts of the start zone were as low as 31 degrees.
Weather
Mostly sunny skies and mild winds down low with stronger winds from the west on Seattle Ridge.
Snow surface
Soft fresh snow from the parking lot to the just below the ridge. Surface hoar was found in the flats and higher up sporadically in isolated areas. On the ridge the snow was wind affected.
Snowpack
We took a look at the crown face on the backside of Seattle Ridge. We found a weak layer of buried surface hoar on the bed surface. These are concerning findings because it means this weak layer was preserved well enough to become a persistent problem.
The soft slab avalanche was at 2300' on a 31-degree northwest slope. The crown averaged 2-4' deep and 300' wide.
See attached photos for detailed snowpack information from the crown profile.
Daniel standing at the crown of an avalanche that was triggered remotely from above yesterday. 01.09.2024
HPAC forecaster Ryan Lewthwaite came down to ride with us, and we put him to work helping us repair the anemometer this afternoon. 01.09.2024
At this point pretty much the enitre uptrack is threatened by open glide cracks. 01.09.2024
Recent large natural avalanche on the front side of Seattle Ridge, just a little south of the uptrack. 01.09.2024
Profile taken at the crown of the avalanche. 01.09.2024
Snow blowing up and out of Zero Bowl this morning with strong northwesterly winds. 01.09.2024