Maryland and the District of Columbia: Floods and Droughts
By R.W. James, Jr., U.S. Geological Survey; "General Climatology" section by W.J. Moyer, Maryland State Climatologist, and A.J. Wagner, National Oceanic and Atmospheric Administration; "Water Management" section by G.T. Setzer, Maryland Department of Natural Resources
Excerpt from Introduction
Precipitation in Maryland and the District of Columbia is derived from moisture transported from the Atlantic Ocean, the Gulf of Mexico, or the Caribbean Sea or is recycled from the midcontinent. Some storms in airmasses that originate in the arctic may be enhanced as they cross the Great Lakes. Annual precipitation in the region of Maryland and the District of Columbia averages about 42 inches. Floods can occur in any season and can affect the entire region. Droughts occur less frequently than floods; however, brief, local, and sometimes severe droughts have been documented.
