Snowmelt can contribute a lot of water to a river in the spring.
Contribution of snowmelt to streamflow
A good way to visualize the contribution of snowmelt to streamflow in rivers is to look at the hydrograph below, which shows daily mean streamflow (average streamflow for each day) for four years for the North Fork American River at North Fork Dam in California (USGS real-time streamflow data). The large peaks in the chart are mainly the result of melting snow, although storms can contribute runoff also. Compare the fact that minimum mean-daily streamflow during March of 2000 was 1,200 cubic feet per second (ft3/s), while during August streamflows ranged from 55-75 ft3/s.