The twister touched down at 9:17 a.m. EDT Monday in Berkeley Heights and pushed through Providence and Summit, the National Weather Service said.
The 50-yard-wide twister was on the ground for about 10 minutes and tore a path 4.8 miles long. Wind gusts of up to 85 miles per hour were confirmed by the weather service.
Berkeley Heights city officials said two homes are uninhabitable after they were crushed by falling trees, and one car was destroyed. No casualties were reported.
"A tornado warning isn't something we usually see in New Jersey," said Michael Howarth, 18, of Berkeley Heights. "I grabbed all my personal documents, passport and birth certificate and all that in my fireproof box and I got into the basement."
Thousands of people were without power after a thunderstorm dropped up to 3 inches of rain by 11 a.m., The (Newark, N.J.) Star-Ledger reported Tuesday.
Several people were stranded in their cars -- five on a commuter bus -- when flash floods caused road closures in central New Jersey, the newspaper said.