Updated 03/01/11 – 11:22 p.m.

CHICAGO (CBS) — An off-duty Chicago Fire Department paramedic was hurt by ice that fell from a building in downtown Chicago near the Loop.

The off-duty paramedic was hit by a chunk of falling ice while he was near the corner of Monroe and Franklin streets near the Loop. Initial reports indicated the ice came from the Willis Tower, located at 233 S. Wacker Dr., but officials at the skyscraper said it was not certain where the ice came from.

There were reports of ice falling from a number of other nearby buildings.

The paramedic suffered a large gash to his head, officials said.

Eyewitness Patrick O’Brien said that shortly before the paramedic was struck, falling ice had smashed through the rear windshield of a car that was pulling into a nearby parking garage.

The paramedic, a 20-year veteran of the Fire Department, was helping to attend to the woman who was driving that car when he was hit in the head by a large chunk of ice, O’Brien said.

The paramedic was taken to Northwestern Memorial Hospital in serious to critical condition. O’Brien said he was conscious and talking a few minutes after being struck, but suffered a severe gash to his head.

A spokesman for the Willis Tower said there was no direct evidence that the ice that struck the paramedic came from the Willis Tower.

“There is no definitive evidence of where the ice is coming from,” Willis Tower spokesman Bill Utter said.

Police and fire crews were responding to several reports of falling from the Willis Tower and other nearby buildings.

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Streets were closed to vehicle traffic in an area bounded by Jackson Boulevard, Wells Street, Wacker Drive and Madison Street, although motorists who had parked in that area were being allowed to drive out. Several sidewalks in that area also were closed down due to the falling ice.

Pedestrians walking through that area were advised to walk close to buildings and, whenever possible, under awnings or building overhangs.

Three years ago, falling ice from the Willis Tower — at the time, still named the Sears Tower — shattered the windshield of an SUV half a block away from the skyscraper.

A huge piece of ice fell and shattered Jane Marcus’ windshield. The ice had broken off Sears Tower, then crashed onto Marcus’ sport-utility vehicle a half block away as she drove west on Quincy Street.

“I was so stunned and really so absolutely numbed by it,” Marcus said at the time. “I’m lucky I wasn’t killed. … Then after we got out of the car there were other huge pieces of ice that kept coming down and it’s a miracle no one was killed who was walking.”

No one was hurt by the falling ice in 2008.

Falling ice is a common problem in downtown Chicago in the winter, a hazard caused by warmer temperatures thawing the ice clinging to skyscrapers.

Due to the height of some buildings and the strength of wind gusts in the Loop, the ice can sometimes hit the ground a long distance away from the building where it fell.