Four climbers slipped down an icy Mount Rainier slope Thursday morning, catapulting two men across a crevasse and dropping two others inside it. Helicopters rescued the injured men.

Rescuers reported that one man slipped, dragging two other climbers and a mountain guide about 40 yards to the 20-foot-deep crevasse, Mount Rainier National Park (search) spokeswoman Lee Taylor said.

The most seriously injured were the climbers who plunged into the crevasse.

Patrick Clemens of Bethlehem, Pa., suffered serious head trauma, along with a broken leg and possibly broken ribs, officials said. Matthew Fisher, 42, of Vernon, N.J., suffered broken ribs and a liver injury.

Both were flown from the peak by Oregon National Guard (search) helicopters.

A hospital official declined to release the condition of Clemens, whose age was not available. Officials said Fisher was in serious condition.

Also injured were Peter Bridgewater, 54, of Singapore, with a dislocated shoulder, and John Lucia, 31, a mountain guide who suffered a head injury, Taylor said. Both were hospitalized in satisfactory condition.

All four were evacuated by early afternoon from Ingraham Glacier (search) at the 12,600-foot level of the 14,411-foot peak.

Other climbing parties were nearby and assisted with first aid and rescue efforts, and Park Service rangers were dropped to the scene by helicopter, Taylor said.

It was the seventh climbing accident requiring a rescue in the past week on Rainier, which has seen one fatality this year, Taylor said.