The Upper Laramie Watershed (HUC 10180010) covers approximately 1,156 square miles in southeastern Wyoming, including the Medicine Bow Mountains. The hydrology of the watershed is dominated by snowmelt, with peak flows occurring in May and June. The snowpack in the watershed typically accumulates from October to April and is monitored by the Natural Resources Conservation Service. The watershed contains several reservoirs, including the Rob Roy Reservoir, which supplies water to the city of Laramie. Surface water in the watershed is generally of high quality, with some exceptions in areas affected by historic mining activities. Interesting climatic facts and trends include a warming trend in the region, with an average annual temperature increase of 2.2°F since the 1950s, and an increase in extreme weather events such as drought and flooding.