About 200 soldiers in A Company, 5th Battalion, 159th Aviation Regiment, and most of their 15 CH-47D Chinook helicopters will go to an undisclosed open-ended assignment overseas in the next few weeks, part of the buildup for the possibility of war in Iraq, officials said.

Steve Winslow, chief high-altitude ranger at Mount Rainier National Park, said there are few alternatives to the large, twin-rotor Chinooks for high-altitude rescue missions.

Other available helicopters have a ceiling of about 9,000 feet, and fixed-wing aircraft that are used to search from the air cannot land on the 14,411-foot peak. Chinooks can operate to about 19,400 feet.

"There's just not that many resources out there that can do what the Chinook can do for us," Winslow said.

About 11,000 climbers attempt the summit between May and September.

"That unit at Fort Lewis has been our anchor," park superintendent Dave Uberuaga said. "If they are back by the first of May, then that would cover the highest percentage of our search and rescue."

If the deployment lasts longer, wildfire control efforts this summer also could be affected. Chinooks are used for hauling buckets of water to drop on forest, range and brush fires around the state.

Pam Garrison, spokeswoman for the 70th Regional Support Command at Fort Lawton in Seattle, said a Navy helicopter unit also might be available for rescue missions while the Army reservists are away.

Capt. Grant Haugen, commander of the unit, said some rescue capacity would remain at Fort Lewis.

Two pilots, three or four flight engineers and other civilian employees are staying at company headquarters, along with at least one helicopter and all search and rescue gear except for a couple hoists.

"It will be much more limited, and it will probably be reserved for the most serious conditions," Haugen said. "People with broken legs and extremities will probably have to be packed out instead."