How did the areas geography contribute to the Tri-State tornado?

The geography impacted the Tri-State tornado in a manner that was extraordinarily conincidental. The tornado just happened to move parallel to a ridge that contained a coal seam. Numerous towns had been built to mine that coal. So, as it moved along that ridge, the tornado hit town after town along its 219-mile-long damage path. This, coupled with the tornado's unusual intensity (F5), rapid movement, and low visiblilty led to an extremely high death toll of 695.