PORTLAND, Ore. - Crews on Sunday night prepared to launch a search for three climbers who may have gotten separated while on the north side of Mount Hood.

Hal Lillywhite, an official with Portland Mountain Rescue, said the trio started hiking Wednesday but it was unclear when they planned to return.

A note left in their rental car at Cooper Spur Ski Area said they planned to climb the mountain's north side, he said.

At some point, one of the climbers called his wife on a cell phone, Lillywhite said, but their location remains unknown.

Officials said the climbers are all from out of state.

"Really we don't know much more than that," Lillywhite said.

Portland Mountain Rescue officials were weighing whether to start the search Sunday night or wait until Monday.

"The question is can we safely go into that environment at this time," he said. "Right now, that's a really good question."