The firm's BrandIndex service surveyed two slices of the U.S. population, adults 18 to 34 and those over 35, to discover if their perception of the Facebook brand has grown more positive or negative over the past few weeks and rating the results on a scale of -100 to 100.
The Tuscaloosa tornado was later given a rating of EF4, the second-most powerful on the Enhanced Fujita Scale, meaning it had wind speeds between 166 and 200 mph.
Two National Oceanic and Atmospheric Administration storm-rating measurements initially ranked Friday's snowstorm as 16th in Northeast history by one scale and 25th by another.