Megadrought

A megadrought is an extended drought. It lasts two decades or more. Megadroughts in the past were linked with La Niña conditions lasting for many years.
The term "megadrought" generally refers to the length of a drought, not its intensity. Multiyear droughts lasting one decade or less, like the Dust Bowl drought of the 1930s, are not a megadrought though they lasted a long time.
Megadroughts have caused people to move away from the drought-affected areas. One example is Ancestral Puebloans in the Southwestern United States.