Spinal Tap Main and Couloir

Quick report

Weather

sunny

Ride Type

alpineSlopes, steepSlopes, sunnySlopes

Stayed Away

convexSlopes

Riding Quality

good

Snow Conditions

crusty, deepPowder

Avalanche Conditions

avalancheConditionSlab, avalancheConditionSnow

Saw slide debris from East Col and descended to meet a party of 3 next to debris. Proceeded to initiate a beacon search as debris appeared fresh. Found no signals. Took photos. Size estimated at size 3.5 (reasoning below). All measurements here are estimates. Two start zones with two merging slide paths, meeting at midpoint and again 150m before Circle Lake. The highest elevation slide, at 20m underneath Spinal Tap entrance, approx. 100m across at the convexity, slid looker's right to the Spinal Tap couloir, curving across skier's left descent from East Col, before meeting the lower slide path at Circle Lake. The lower slide: looker's left and 30m below the higher slide, also some ~100m across, slid and released the entire rocky face, extending significantly to looker's left. Using binoculars, crowns estimated at 1.5m on both slides. Debris piles measured up to 2.5m. Total width at estimated 400–500m, with length some 45% of Circle Lake, with debris length ranging close or exceeding to 700m+. Debris was piled with hard chunks approaching concrete density. The ice was cracked around Circle Lake with fissures down 3m+ (be careful!). Of note to travellers: the slide slid across the standard skier's right descent from East Col, and slid directly across and over most of Circle Lake, where many parties transition. It also slid directly across the standard uptrack to Body Bag Bowl. Look up! After exiting the zone to Body Bag Bowl, I called in to Blackcomb Patrol and was informed the slide had been skier triggered, remote, from a rider standing on the ridge, with no involvement. I also was informed a previous party had reported it in the morning, with estimated time of the slide at 10am. Was informed slide was 2.5 to 3. Size 3.5. From below the width and length can be appreciated, in part because it is not one, but two start zones produce two merging flows. The two flows appeared to collide with some violence, evidenced by large debris piles and the cracking of the lake ice. The debris pile is deep, wide, piled with hard blocks. The cliffs above have crowns of piled debris and rock has been exposed. The slide in its destructive potential is possibly closer to a 3.5+. Of note, prior to this incident I observed 4 snowboarders bootpacking up East Col without avalanche kit. I made every effort to discourage them. We have been receiving massive snowfall on suspect layers.. Thankfully, they chose the route out Body Bag Bowl from South Col. I was glad to see them exit safely. I chose to share knowledge of consequence with a party venturing into the backcountry unprepared, and after seeing the slide debris, was glad I did. Travel safely everyone. - tcV

Weather

Wind Speed

windSpeedCalm

Sky Condition

clear

Storm Start Date

2025-03-08

Temperature Trend

rising

Precipitation Type

none

Snowpack

Obs Type

summary

Site Aspect

E, N, S, SE, SW, W

Ski Penetration

30

Foot Penetration

50

Site Elevation Band

alp

Surface Conditions

newSnow, variable

Avalanche

Run Length

700

Slab Width

250

Trigger Type

skier

Wind Exposure

windwardSlope

Avalanche Size

3.5

Slab Thickness

150

Trigger Sub Type

remote

Start Zone Aspect

S, SW

Trigger Distance

20

Vegetation Cover

openSlope

Start Zone Incline

40

Avalanche Character

deepPersistentSlab, persistentSlab, stormSlab

Crust Near Weak Layer

1

Number Of Avalanches

2-5

Start Zone Elevation

2300

Runout Zone Elevation

2000

Weak Layer Burial Date

2025-03-04

Avalanche Observation

12hrsAgo

Weak Layer Crystal Type

stormSnow, surfaceHoarAndFacets

Start Zone Elevation Band

alp

Avalanche Occurrence Datetime

2025-03-14T17:00:00.000Z

See main comments. The slide revealed the prevailing rocky and icey windward slope with consistent sun exposure. Slide down to potential March 4th PWL.