A 43-year-old man from Estes Park is presumed dead after being caught in an avalanche in Rocky Mountain National Park on Sunday, according to park spokeswoman Kyle Patterson.

Search efforts began this morning for two overdue climbers from Estes Park, Patterson said. At about 2:45 p.m., park rangers found 45-year-old climber Lisa Foster in the upper Fay Lakes basin, about six miles from the Lawn Lake Trailhead.

Foster told rangers that she and her partner, David Laurienti, were caught in an avalanche at about 6 p.m. Sunday when descending from the north side of Blitzen Ridge on the 13,514-foot Ypsilon Mountain.

Laurienti is presumed dead, and Foster suffered numerous injuries, Patterson said. Park rangers are providing medical care and evacuating Foster by toboggan from Ypsilon Lake, which is about 4.5 miles from the Lawn Lake Trailhead, Patterson said. The team is expected to reach the trailhead close to midnight.

Foster, who has worked as a Rocky Mountain National Park field technician, has hiked and climbed to every named destination in the park and wrote "Rocky Mountain National Park: The Complete Hiking Guide" in 2005.

Blitzen Ridge on Ypsilon Mountain is a challenging mountaineering route that includes sections of technical rock, often made more difficult in winter conditions, Patterson said. Recent snow and winds have contributed to what the Colorado Avalanche Information Center deemed considerable avalanche conditions in the area since Saturday, she said.

She said park rangers will start the body recovery effort when conditions allow.