The winter storm could impact up to 170 million people across more than 20 states from the southern Plains to the Midwest and East, AccuWeather said.

Through March 2, the U.S. had totaled 61 confirmed tornadoes this year, less than half the yearly average of 138 for that period. That figure is about to change, according to DaSilva, who said the number of twisters is less relevant than where and when they strike.