Analogous to a snow avalanche on a steep mountain slope, an incoming light pulse initially frees just a few charge carriers which in turn free others until the original signal is amplified many times.

This disaster is one of the most devastating examples of a very common event: an avalanche of snow or ice.

The kind of avalanche that destroys trees, cars, buses, even houses! Tens of thousands of tons of snow were coming straight down the mountain behind me.