Snowmelt is water that comes from snow as it melts and turns back into liquid. When winter ends and temperatures rise, all that accumulated snow doesn't just disappear: it melts gradually, releasing water that flows into streams, rivers, and underground water supplies.

In many parts of the world, snowmelt is the primary water source for entire regions. Cities like Los Angeles and Denver depend heavily on snowmelt from nearby mountain ranges. Farmers in California's Central Valley rely on snowmelt flowing down from the Sierra Nevada to irrigate their crops throughout the dry summer months. Scientists carefully measure the snowpack (accumulated snow in the mountains) each winter because it tells them how much water will be available when the snow melts in spring and early summer.

The timing and amount of snowmelt matter enormously. Too much melting too fast can cause flooding, washing out roads and bridges. Too little snowmelt means water shortages later in the year. Climate scientists track snowmelt patterns to understand how changing temperatures affect water supplies for millions of people.