This from Tim Olk:

Chicago ice dive training at 31st Street each

fire department divers training in cold water

Tim Olk photo

fire department diver training in cold water

Tim Olk photo

fire department divers training in cold water

Tim Olk photo

fire department diver training in cold water

Tim Olk photo

fire department diver training in cold water

Tim Olk photo

fire department diver training in cold water

Tim Olk photo

fire department diver training in cold water

Tim Olk photo

fire department diver training in cold water

Tim Olk photo