Bonnington Wind Slab

Quick report

Weather

sunny, cold, windy

Ride Type

steepSlopes, openTrees, alpineSlopes

Stayed Away

sunnySlopes, convexSlopes

Riding Quality

terrible

Snow Conditions

hard, windAffected

Avalanche

Run Length

150

Slab Width

25

Trigger Type

skier

Wind Exposure

leeSlope

Avalanche Size

2.5

Slab Thickness

30

Trigger Sub Type

accidental

Start Zone Aspect

NE

Avalanche Character

windSlab, persistentSlab

Number Of Avalanches

1

Start Zone Elevation

1900

Weak Layer Burial Date

2020-02-23T04:03:31.000Z

Weak Layer Crystal Type

surfaceHoar

Start Zone Elevation Band

alp

Avalanche Occurrence Datetime

2020-03-01T14:00:00

Incident

Group Size

2

Group Activity

skiing

Number Injured

2

Number Involved

2

Number Fully Buried

0

Snow Depth Trigger Point

shallow

Terrain Shape Trigger Point

concave

Went hoping to find high North aspects holding good snow but found that the high winds had beat down everywhere. Decided to ski a protected NE facing chute hoping for better snow. Skier 1 decided to ski cut under the cornice hoping to release wind deposit and clean out the chute, found that snow was rock hard wind hammered. Skier 2 stepped onto slope on a ridge above and W of chute, snow also hard, then proceeded to ski cut over to skier 1. Slope released at 10cm point and propagated into chute above skier 1, 30cm deep. Skier 1 managed to hold ground while snow moved around, skier 2 caught and pulled airbag carried about 10m before managing to anchor into bed surface. Humbling. Avy ran down chute and into bowl below propagating a few pockets along the way. Slab was very dense and fractured into big blocks. Bed surface was very hard and likely failed on Feb 22 SH.