how did Salang Tunnel 2010 avalanches happen

The 2010 Salang avalanches were triggered by a sudden blizzard in the Hindu Kush that brought heavy wind, rain, and intense snowfall, which destabilized the slopes above the road and tunnel approach. That weather set off a chain of at least 17 avalanches that buried more than two miles of highway and trapped travelers.

What happened

A storm moved in quickly over the Salang Pass area, and the combination of heavy precipitation and strong winds overloaded the snowpack on steep mountain terrain. Once the snowpack failed, multiple avalanches released in succession and swept down onto the highway.

Why it was so bad

The road at Salang is a critical high-altitude route through the Hindu Kush, so when avalanches blocked it, vehicles were trapped with little room to escape. The situation worsened because the avalanches came in a series rather than as one isolated slide, which made rescue and clearing operations much harder.

In plain terms

Think of it as a mountain slope that had been loaded with too much fresh snow too fast; then wind and rain helped tip it over the edge. The result was not one avalanche, but a burst of them across the same corridor.

TL;DR

A sudden severe snowstorm, with heavy wind and rain, destabilized the mountains above Salang and triggered a cascade of avalanches that buried the highway and trapped travelers.