Gov. Deval Patrick has called in the National Guard.
Residents of 19 small communities in central and western Massachusetts were left to deal with widespread damage, one day after at least two late-afternoon tornadoes shocked emergency officials.
The tornadoes were a rare sight, far north of tornado alley. Massachusetts has not seen a tornado since 2008.
Two people were killed in West Springfield and another in Brimfield, authorities said. A Springfield death previously blamed on storms may have been an unrelated heart attack, Patrick said Thursday.
Patrick told "Good Morning America" that considering how quickly the tornadoes formed, he feels fortunate there weren't more fatalities.
"When I spoke with the mayor of Springfield yesterday, he told me they had about ten minutes' warning," Patrick said.
"When you consider how quickly the tornadoes developed and then touched down, the fact that there wasn't even greater damage and loss of life is a remarkable thing."
The last killer tornado in Massachusetts was on May 29, 1995, when three people died in Great Barrington, a town along the New York state border.
Tens of thousands of residents were left without electricity.
Springfield Mayor Domenic Sarno said more than 40 people were admitted to hospitals in the city after Wednesday's tornado. State police said at least 5 people were seriously injured and required surgery.
In Sturbridge, at the junction of the Massachusetts Turnpike and Interstate 84, a half-mile section of Main Street was shut down after a tornado damaged homes and felled trees, according to town administrator Shaun Suhoski.
Suhoski said some people suffered "cuts, scrapes, bruises," though no serious injuries were immediately reported. The storm blew trees into houses and severely damaged telephone poles and rooftops, he said.
U.S. Sen. Scott Brown planned a tour on Thursday of the areas hardest hit by the tornadoes.
The Associated Press contributed to this report.