GRAND CANYON NATIONAL­ PARK — Authorities searched Grand Canyon National Park on Monday for a teen and his stepgrandmother who were swept away as they tried to cross a creek.

Two fellow hikers alerted officials over the weekend by setting off an emergency GPS locator beacon below the canyon’s North Rim, Chief Ranger Matt Vandzura of the National Park Service said.

He said the 14-year-old boy and 62-year-old woman were swept away Saturday in a tributary of the Colorado River.

The McCallie School, an all-boys school in Chattanooga, Tenn., said one of its students, eighth-grader Jackson Standefer, and his stepgrandmother were carried downstream.

The teen’s family identified the stepgrandmother as Lou-Ann Merrell, wife of Randy Merrell, founder of the Merrell Boot Co.

Vandzura declined to identify the missing pair or the other hikers. He said it was too soon to know what went wrong. No rain or flash flooding was reported but it was not known whether the water level was higher than usual.

The Park Service describes conditions in the area on its website, warning that melting snow or heavy rain may make crossing the creek impossible.

An Arizona Department of Public Safety copter searched for the missing pair Saturday night. The Park Service sent a helicopter and ground crews Sunday. The Park Service resumed the search Monday.

Associated Press