CHICAGO — Two parachutists were seriously injured Saturday during the Chicago Air & Water Show, including one who witnesses say clipped the top of a high-rise apartment building and fell to the ground in the city's Gold Coast neighborhood.

The two men were taken in serious-to-critical condition to Northwestern Memorial Hospital on Saturday morning, Fire Department spokesman Juan Hernandez said.

Witnesses told first responders that at least one of the parachutists collided with a building in the upscale lakefront district, but the Fire Department had not confirmed the accounts.

Spectator Heather Mendenhall told the Chicago Tribune she was watching the show from a rooftop and saw one of the parachutists strike the roof next door with his feet and fall, with his parachute trailing behind him.

"His legs caught the tip of the roof, and then he fell over. It was horrible," she told the newspaper.

She said he looked unconscious as he hit the roof. A maintenance worker on the same roof called paramedics, she said.

"If he was only one foot closer to the roof, the maintenance guy could've grabbed him," Mendenhall said.

The other parachutist was found on North Avenue Beach, near the main viewing area for the show, Hernandez said.

He had no other details on the nature of the injuries or what went wrong.

One of the performers is with the U.S. Navy's Leap Frogs team, according to WBBM-TV. The station published a photo of him receiving treatment on the beach.

The annual two-day air show draws millions of people to Chicago's Lake Michigan shoreline. Headliners include the U.S. Navy Blue Angels.

The U.S. Army jump team known as the Golden Knights is also in the show.

Representatives for the Army and Navy parachute teams did not respond to email and voicemail messages seeking comment.

Members of the Navy team are active-duty personnel drawn from forces including the Navy SEALs. Jumpers can reach speeds of up to 180 mph during freefall by pulling their arms to their sides. They typically open their parachutes at around 5,000 feet, joining their canopies together in formation and setting off smoke grenades to send red smoke trailing behind them.

Sign Up for Daily Headlines

Sign-up to receive a daily email of today’s top military news stories from Stars and Stripes and top news outlets from around the world.

Sign up