Three mountain climbers — two from the U.S. and one from Canada — missing for five days on Aoraki, New Zealand's tallest peak, are believed to have died in a fall, the authorities said Friday. The Americans — Kurt Blair, 56, from Colorado and Carlos Romero, 50, of California — were certified alpine guides, according to the website of the nonprofit American Mountain Guides Association. New Zealand authorities have not named the Canadian climber at the request of his family.