Glacier runoff is the water that comes from rain falling on or the melting of a glacier. Runoff water flows into rivers, lakes, and oceans changing their shape, depth, span, flow rates, chemistry, environment, and more. Runoff matters for many reasons. For example, many animal and human communities depend on runoff to reliably fill rivers, lakes, and reservoirs for drinking water. If there’s too much runoff water coming from a glacier, it can cause downstream flooding. The time of year a glacier is melting and producing runoff is important, too. Because of climate change, many glaciers are melting earlier in the spring, swelling rivers sooner than usual, which can alter seasonal habitat, animal behavior, and spawning patterns.

Researchers and planners can use NASA’s data to measure glacier runoff amounts and timing to determine what it means for the form and function of Earth’s landscapes and waterways, natural and animal communities, and people.