Louisiana is a state in the southern United States with a humid subtropical climate. The state has many major surface water flows, including the Mississippi River, the Atchafalaya River, the Red River, the Ouachita River, and the Sabine River. These rivers and their tributaries are subject to flooding during the state's frequent severe weather events, such as hurricanes and tropical storms. Louisiana also has numerous reservoirs and dams used for flood control and hydroelectric power generation. The state's hydrology is influenced by its flat terrain and extensive wetlands, which act as natural reservoirs. Snowpack is generally not a significant factor in Louisiana's hydrology, but heavy rainfall events can lead to flash flooding and river flooding.