According to Ameren Missouri, tens of thousands of customers were without power, mostly in St. Louis City, south St. Louis County, west county, and Jefferson County.
In Illinois, nearly 10,000 customers in St. Clair, Madison, and Macoupin counties were without power Wednesday morning, Ameren Illinois said.
Several flights have been cancelled out of Lambert-St. Louis International Airport.
FOX 2 Meteorologist Chris Higgins is live in the Storm Pilot with more.
Snow fall rates could top one inch per hour through 7 a.m. and gusty winds are expected near 40 miles per hour throughout the afternoon.