Remote Trigger Size 2.5-3 Mosquito Mountain

Avalanche date/time

Tuesday, April 4, 2023 at 17:00

Estimated occurrence time of avalanche

Less than 12 hours ago

Number of avalanches in this report

1

The size of avalanche

2.5

Slab thickness

75cm

Slab width

200m

Run length

800m

Avalanche Character

• Deep persistent slab
• Persistent slab
• Wind slab

Trigger type

Skier

Trigger subtype

Remote

Remote trigger distance

300m

Start zone aspect

• S
• SE

Start zone elevation band

• Alpine

Start zone elevation

2,750m

Start zone incline

35°

Runout zone elevation

2,500m

Weak layer crystal type

• Facets

Vegetation cover

Open slope

While ascending mosquito mountain on skis, we were sticking to the "safest" terrain. After passing a higher risk spot of 30-35 degree snow on a south slope we gained the ridge, a couple hundred meters later and felt a massive whumpf (very loud and felt it shake underfoot) likely triggered from a thick to thin zone. Regrouping in a safe zone revealed a large remotely triggered avalanche that initiated 250-300m away below a convexity on a south facing planar slope around 35 degrees. We estimated size 2.5-3. It went full depth and exposed multiple layers in the upper debris. We noticed a shooting crack traveled at least 300m (in one direction) above the crown on terrain that didn't slide and was below 30 degrees. Avalanche occured around 11:00 and was on and off cloudy with solar input, but the fresh dusting (5-10cm) remained light and saw minimal effects of solar warming in the morning. There was no noted wind or storm slabs at triggering location and obviously didn't expose ourselves to the fractured slope to investigate the area further, however, terrain similar (slightly lower angle) before and after felt quite stable.

Red arrow indicates where we approximately at trigger.