20210208 Knox Creek Avalanche Fatality Report by Dallas Glass and Matt Primomo

Incident snapshot

Occurrence Time and Date: Approx. 1100 am Monday, February 8, 2021 Time First Reported to SAR: 1240 pm Recovery/Rescue Time: Approx 700 pm Lat/Lon: 47.35012, -121.19072 Location: Knox Creek, Kittitas County, Okanogan-Wenatchee NF, WA Number in Party: 2 Number Caught: 2 Number Partially Buried, Critical or Not-critical: 1 not-critical Number Completely Buried: 1 Duration of Burial: Approx. 8 hrs Number Injured: 0 Number Killed: 1

Avalanche Type: HS (Hard Slab) Trigger: AV (designation includes snow biking) Size: R3/D3 Start Zone Aspect: NE Start Zone Angle: 30-55+ Start Zone Elevation: Average 4750’

Height of Crown Face: Average 4-5’ Width of Fracture: 700-800’ Vertical Fall: Maximum 450’ Slab Characteristics: DF/RG, 1mm/0.5mm, F-1F+ Weak Layer Characteristics: FCxr, 1mm Bed Surface Characteristics: K, MFcr, 3mm, Mid-Jan crust Avalanche Classification: HS-AV-R3-D3-O

Burial involved a terrain trap: No Number of people that crossed start zone before avalanche: 0 Avalanche occurred during: Snow biking, side-hilling Location of group in relation to start zone during avalanche: The pair was in the lower portion of the startzone.

Avalanche Safety Gear Carried: Both riders carried shovel, beacon, and probe. Rider 2’s beacon was found in the off position. Rider 2 was wearing an avalanche airbag. The airbag was inflated. Avalanche Training and Experience at Activity: n/a Signs of Instability Noted by Group: n/a Extent of Injuries or Cause of Death: n/a NWAC Forecast Zone: East Slopes Central Avalanche Danger Rating (Above, Near or Below Tree-line): Avalanche Danger was forecast to be Considerable in all elevation bands. Summary On Monday, Feb 8th, a party of two were snow biking in the Knox Creek drainage near Salmon la Sac. (French Cabin Creek SnoPark) The two riders were traveling on parallel tracks across the slope when they triggered a very large avalanche. Both men were caught and carried in the slide. The lead rider (Rider 1) was partially buried and able to dig himself out. The trailing rider (Rider 2) deployed his airbag but was fully buried. Rider 1 immediately began searching for his friend including a visual and beacon search but was unable to locate him. After approximately 30 min, Rider 1 descended towards the trailhead to call for help. Rider 1 reported the incident to 911 through a 3rd party. Search and Rescue was called out at 12:40 pm. After initially finding other large avalanches on a nearby slope, SAR arrived at the accident site at 4:28 pm and immediately began searching with beacons, 2 avalanches rescue dogs, and probing likely catchment areas. At approximately 6 pm, the SAR regrouped away from the debris to prepare for night operations. The 2 avalanche rescue dog teams were sent back to the site to resume searching. One of the dogs alerted just prior to 7 pm. The alert was confirmed with a probe strike, and Rider 2 was dug out from the snow. He was found 4’ deep with his airbag pack inflated. While Rider 2 was carrying avalanche rescue gear, his beacon was found in the off position. His snow bike was located uphill by probe strike after Rider 2 had been removed from the area. NWAC staff returned the following day, Tuesday, February 9th 2021 to conduct an accident investigation and take additional photos.

All photos by Dallas Glass and Matt Primomo Feb 8th or 9th

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