Connecticut has two main watersheds: the Connecticut River that flows from the northern border down to Long Island Sound, and the Housatonic River that flows from the western border before emptying into Long Island Sound. There are several large reservoirs and dams in the state, including the Barkhamsted Reservoir and Colebrook River Lake. Climate conditions in Connecticut vary from warm and humid summers to cold and snowy winters, which directly impact snowpack and streamflow. Additionally, Connecticut is susceptible to hurricanes and tropical storms, which can cause significant flooding. Connecticut's hydrology is highly influenced by the state's relatively small size, densely populated urban areas, and topography. The state's major rivers and tributaries are closely monitored by the USGS for water quality and quantity.