Natural avalanche observed on Pump South Face

Quick report

Weather

sunny, warm

Stayed Away

steepSlopes, sunnySlopes

Snow Conditions

heavy, wet

Avalanche Conditions

avalancheConditionSlab, avalancheConditionTemp

We were hiking on the Mount Seymour Trail when we observed a naturally occuring avalanche in front of us. The avalanche occured at 2:52PM on the South face of Pump Peak between elevations 1300m and 1340m on a slope of 31 degrees. The avalanche started with a loud rumbling sound "VRRRRROOOMM" that lasted between 1.5 to 2.5 seconds, and we saw some of the debris sliding down the open slope for 10 to 20 seconds. The debris then reached a patch of trees and slowed down. From there, sluff snow started dripping down the nearby slopes, which lasted over two minutes. When the avalanche occured, we were at elevation 1250m and we had just left Simple terrain. we were testing the stability of the snow on a small test slope in inconsequential terrain. On the solar irradiated South aspect, pinwheels and sluff were easily generated from the top 5-10cm of snow and the snow was moist. On the West aspect, there was no pinwheeling. Off of the hiking trail, the snow was wet, loose, and granular and it was easy to sink into the snow (post-holing) from 20-60cm deep.

Weather

Avg Temp

8

Max Temp

10

Min Temp

4

Wind Speed

windSpeedCalm

Sky Condition

clear

Temperature Trend

rising

Snowpack

Obs Type

point

Site Aspect

SE

Site Elevation

1250

Test Initiation

easy

Foot Penetration

40

Test Failure Depth

5

Site Elevation Band

tln

Test Failure Layer Crystal Types

other

We picked a small test slope (35-40 degrees) to quickly test the stability. On the solar irradiated South aspect, by kicking the snowpack pinwheels and sluff were easily generated from the top 5-10cm of snow and the snow was moist. On the West aspect, the snow surface was a thin crust and no pinwheels/sluff could be generated by kicking. Off of the hiking trail, the snow was wet, loose, and granular and it was easy to sink into the snow (post-holing) about 20-60cm deep.

Avalanche

Trigger Type

natural

Avalanche Size

1.5

Start Zone Aspect

S

Vegetation Cover

sparseTrees

Start Zone Incline

31

Avalanche Character

looseWet, wetSlab

Number Of Avalanches

1

Start Zone Elevation

1340

Runout Zone Elevation

1310

Avalanche Observation

12hrsAgo

Start Zone Elevation Band

tln

Avalanche Occurrence Datetime

2025-03-01T22:52:00.000Z

The avalanche occured at 2:52PM on the South face of Pump Peak between elevations 1300m and 1340m on a slope of 31 degrees. The avalanche started with a loud rumbling sound "VRRRRROOOMM" that lasted between 1.5 to 2.5 seconds. We saw some of the debris sliding down the open slope with sparse trees for 10 to 20 seconds. The debris then reached a patch of trees and slowed down. From there, sluff snow started dripping down the nearby slopes, which lasted over two minutes.