OMAHA, Neb. — A tornado near a mall in central California swept up cars, uprooted trees and sent several people to the hospital. In San Francisco, authorities issued the first-ever tornado warning. Elsewhere, inclement weather plagued areas of the U.S., with dangerous conditions including heavy snow in upstate New York, a major ice storm in Midwest states and severe weather warnings around Lake Tahoe. [time-brightcove not-tgx=”true”] The ice storm beginning Friday evening created treacherous driving conditions across Iowa and eastern Nebraska Friday and into Saturday and prompted temporary closures of Interstate 80 after numerous cars and trucks slid off the road.