PORTLAND, Ore. (AP) _ One of two teen-age survivors rescued from a snow cave on Mount Hood reacted with quiet resignation when told his legs had been amputated further, hospital officials say.

Giles Thompson of Longview, Wash., underwent surgery Friday. Doctors intended to prepare him for the fitting of artificial legs, but the surgery revealed more muscle damage from frostbite, a hospital spokeswoman said.

His legs had been amputated Sunday at midcalf because of circulation and bleeding problems that threatened his life.

During four hours of surgery Friday afternoon, the youth's right leg was further amputated at the knee, and his left leg was amputated just below the knee, said Barbara Hood, a spokeswoman at Providence Medical Center.

''They were anticipating some cleaning-up kinds of things,'' Ms. Wood said. ''I don't think they anticipated they would have to amputate to that extent.'' Thompson, 16, was listed in serious but stable condition.

The boy was found with seven others May 15 after spending three days and nights in the cave. The only other survivor pulled from the cave, Brinton Clark, 16, remained in good condition at Emanuel Hospital. She suffered minor frostbite but did not require amputation.

Ms. Hood said Thompson will require more surgery on the left leg next week to prepare it for a prosthesis. Depending on what's found during that operation, more surgery may be required, she said.

Doctors also closed and grafted skin on cuts made during earlier surgery to relieve swelling and pressure on Thompson's arms. His arms appear healthy, but it may be six or seven months before doctors know if he has suffered any disability in his right arm, Ms. Hood said.