Remote Trigger Size 2.5-3 Mosquito Mountain

Date/heure de l'avalanche

mardi 4 avril 2023 à 17 h 00

Estimation de l'heure d’occurrence de l’avalanche

< 12 heures

Nombre d'avalanches dans ce rapport

1

Taille de l’avalanche

2.5

Épaisseur de la plaque

75cm

Largeur de la plaque

200m

Longueur d'écoulement de l'avalanche

800m

Caractère de l'avalanche

• Plaque profonde et persistante
• Plaque persistante
• Plaque à vent

Type d'élément déclencheur

Skieur

Sous-type d'élément déclencheur

À distance

Distance du déclenchement à distance

300m

Versant de la zone de départ

• S
• SE

Bande d'altitude de la zone de départ

• Alpin

Altitude de la zone de départ

2 750m

Inclinaison de la zone de départ

35°

Altitude de la zone de dépôt

2 500m

Type de cristaux de la couche fragile

• Grains à faces planes

Couverture forestière

Pente dégagée

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.