Florida is characterized by a flat landscape with numerous rivers and lakes that are critical to the state's hydrology. The St. Johns River, the longest river in Florida, flows from its headwaters in east-central Florida to the Atlantic Ocean. Other major rivers include the Kissimmee River, the Ocklawaha River, and the Apalachicola River. The state's climate is subtropical, with hot and humid summers and mild winters, and is prone to frequent hurricanes and tropical storms. There are numerous man-made reservoirs in Florida, including Lake Okeechobee, which is the largest freshwater lake in the state and a key water source for agriculture and urban areas. The state does not receive significant snowfall, and its hydrology is primarily influenced by rainfall patterns, groundwater recharge, and coastal tides.