Flash floods are dangerous. A little rain in the mountains can send torrents of rushing water
downstream that can damage trees, houses, and even people if they're in the way. If you see a flood is coming, stay far away from rivers and gullies.
In the video below, a flash flood appears in only a few seconds, turning a dry riverbed into a raging torrent of water. Take a look:The leading edge of the water is slow, but that's only because it's weighed down by dirt and debris. Don't be fooled. Even though the water is moving slowly, it's still powerful enough to destroy trees and people.
If there's a flash flood warning near you, get to high ground and stay there.
Source: Trent Shue via Digg