The scariest part of scuba diving under ice for Joe Collins of Eldridge is knowing there's a ceiling 9 inches thick above you.
"You just can't go up," Collins said Saturday.
He spent 17 minutes in water that was 36 degrees. Afterwards, he climbed out, where the air was crisp and the temperature was in the teens.
"Lovely weather," Collins smirked to his scuba instructor, Scott Jones of Davenport, before heading into a warming tent.
"It was a bit shocking how cold the water was," Collins said.
He had to perform two more dives Saturday as part of his scuba ice diving certification.
While Collins was under water, his dive tender, Derek Erickson, also of Eldridge, was on top of the ice holding a rope attached to Collins.
Collins, a paramedic with Genesis Ambulance in DeWitt, Iowa, has been scuba diving for five years.
"It's another chance to play in the water," he said.
Jones trains 200 to 300 new students a year through his business, Scuba Adventures QCA of Bettendorf. His father started the business in 1960.
Jones said he has done more than 10,000 dives all over the world. His favorite dive was around the island of Fiji in the South Pacific.
James Allen, a native of Hawaii and civilian employee of the Rock Island Arsenal, joined Saturday's ice scuba dive. Though he has been on thousands through his active duty service in the U.S. Army, he said Saturday's dive under the ice was the most "extreme" because of the cold.
"It takes a little to adjust to the cold," Allen said.
He likes to scuba dive because of the tranquility. "It's just a peaceful experience," he said.