is a term which is used to refer to lightning strikes occurring without precipitation.
The term is a technical misnomer
is obviously not wet in any instance, and also because the thunderstorms which are so named actually do produce precipitation
, although it does not reach the ground. Such thunderstorms are most common in the western portion of the United States during the summer. They occur when the rain produced by thunderstorms falls through a substantial layer of very dry air which evaporates the precipitation before it reaches the ground.
Dry thunderstorms are notable for two other reasons: they are the most common natural cause of wildland fires, and they can produce strong gusty winds at the surface.
Clouds do not have to be formed of water droplets to produce electricity. Pyrocumulus clouds produce lightning for the same reason that it is produced by cumulonimbus clouds. When the higher levels of the atmosphere are cooler, and the surface is warmed to extreme temperatures due to a wildfire, volcano, etc, convection will occur, and the convection produces lightning.