When permafrost thaws, water can flow more quickly through the ground, creating a complex subsurface flow system. Researchers at the Barrow Environmental Observatory in Alaska gained insight into this process by taking daily measurements of the electrical resistivity of the ground. The results show that vegetation and the snowpack that accumulates on the vegetation in winter control the temperatures of the ground and the flow of water in the ground. Where snow accumulates, ground temperatures stay warmer and water and energy from snowmelt and rain can flow through the ground quickly. Where the snowpack is thin, ground temperatures are colder, preventing the flow of water.