Rainwater in Yellowstone begins as snowfall on high-elevation plateaus and summer showers that infiltrate thin soils or run off quickly into streams. Gravity drives this water downhill through porous volcanic layers, fractured bedrock, and saturated soils, feeding rivers, geysers, fumaroles, and lakes while also contributing to the park’s vast groundwater system. This overview explains where Yellowstone’s rain and melted snow go, how they move through different routes, and how they ultimately leave the region as river flow and vapor.
