One of my 4th grade students asked me if tornadoes west of the continental divide swirl in an opposite direction from tornadoes east of the divide?
Southwest Chicago Christian School Oak Lawn
Dear Mrs. Jousma and class,
The continental divide is an imaginary line that follows a continuous mountain ridge that divides a watershed into two drainage basins. In North America, it separates drainage between the Pacific and Atlantic oceans and extends from northwest Alaska through the Canadian and U.S. Rockies then south through Mexico’s Sierra Madres into Central America. It has no effect on tornado rotation. The vast majority of tornadoes in the Northern Hemisphere rotate counterclockwise due to Earth’s rotation, though there have been documented cases of clockwise spin. South of the equator most twisters rotate clockwise, also with a few exceptions.