Learn — FloodWatch

A flood is water covering land that is normally dry — from a river overtopping its banks, intense rain overwhelming drainage, snowmelt, or storm surge at the coast. FloodWatch focuses on river and stream gauges: instruments that measure how high and how fast the water is at thousands of points along waterways.

• 📏How river gauges measure a floodStage vs. discharge, the action/minor/moderate/major thresholds, and why a small stream can be deadlier than a big river.
• 🌊The main types of floodingFlash floods, river (riverine) floods, urban floods and coastal surge — different speeds, causes and dangers.
• 🚗Why “turn around, don’t drown” worksThe physics of moving water, the danger of flooded roads, and how to act on a flood warning.