Snowball effect

Snowball effect is a figurative term for a process that starts from an initial state of small significance and builds upon itself, becoming larger (graver, more serious), and perhaps potentially dangerous or disastrous...
The common analogy is with the rolling of a small ball of snow down a snow-covered hillside. As it rolls the ball will pick up more snow, gaining more mass and surface area, and picking up even more snow and momentum as it rolls along.
Most of the disasters that happen in and around nature are indeed a replication of this snowball effect, whether it is a an earthquake, a sandstorm, a cyclone or a impulse transmission in our nerve cells or the disasters that occur in our life, everything begins in a small way and hits us when it gathers momentum.