Us Meteriological Department

Tornadoes in the United States are increasingly coming in swarms rather than as isolated twisters, according to a study by US government meteorologists published on Thursday that illustrates another trend toward extreme weather emerging in recent years.

Tornadoes in the United States are increasingly coming in swarms rather than as isolated twisters, according to a study by US government meteorologists published on Thursday that illustrates another trend toward extreme weather emerging in recent years.