WASHINGTON, March 17 (Reuters) - U.S. homebuilding fell more than expected in February as severe cold gripped many parts of the country, in a temporary setback for the housing market, which remains supported by extremely lean inventories amid strong demand for larger homes. Housing starts dropped 10.3% to a seasonally adjusted annual rate of 1.421 million units last month, the Commerce Department said on Wednesday. Economists polled by Reuters had forecast starts would drop to a rate of 1.560 million units in February. (Reporting by Lucia Mutikani; Editing by Edmund Blair)