CHESTERTON | The National Weather Service in Romeoville, Ill., has confirmed that Wednesday evening's storm in Chesterton was a tornado.

Meteorologist Charles Mott said the tornado was categorized as EF 2 on an scale of 5.

The tornado left a swath of destruction 60 yards wide over 2.5 miles, Mott said. Peak winds were estimated at 120 mph, he said.

At a news conference Thursday night, Chesterton Fire Chief Mike Orlich addressed questions about why sirens weren't activated prior to the tornado.

He said the tornado warning had expired but minutes later one was sighted. Simultaneous to the sighting, the warning was issued by the National Weather Service, but the sirens didn't activate. He said officials will investigate why that system didn't sound.

Emergency crews, firefighters, friends and neighbors didn't wait until Thursday morning to begin cleaning up the debris from roads and yards after Wednesday night's tornado.

Joe Saikin, a resident of Eighth Street, said crews from Chesterton and nearby towns were dispatched to the area immediately after the storm moved southwest to northeast from County Road 1100 North to County Road 100 East and left a swath of damage about five blocks wide in its wake.

Chesterton Middle School and an apartment complex at Third and Brown streets appeared to be among the most severely damaged buildings.

Doyle said the apartment complex "suffered catastrophic damage to the structure."

Duneland Schools Superintendent Dirk Baer said three-quarters of the middle school gymnasium was torn off the building, prompting school officials to cancel classes districtwide. A glass atrium at the school also was severely damaged. There was minor water damage in a few of the classrooms.

Baer expected schools to reopen today.

-- Times staff writer Lauri Harvey Keagle and correspondent Heather Augustyn contributed to this report.