An urgent search is underway for a mother and daughter who vanished while hiking one of Southern California’s most demanding mountain trails. Krystal Meyers, 41, and her daughter, Alexis Meyers Martinez, 21, disappeared Thursday while hiking the Vivian Creek Trail in the San Gorgonio Wilderness, according to the San Bernardino County Sheriff’s Department.

Authorities stated the pair were last seen around 11 a.m. at an elevation of approximately 10,300 feet above the High Creek switchbacks before all contact was lost. Search crews are now scouring the remote wilderness in hopes of locating the missing hikers.

The Vivian Creek Trail is considered one of the most grueling routes in the San Gorgonio Wilderness, climbing steeply toward the summit of Mount San Gorgonio, the highest peak in Southern California. According to the U.S. Forest Service, it is both the shortest and steepest route to the summit and is recommended only for experienced mountaineers due to its rugged terrain and demanding conditions.

The San Gorgonio Search and Rescue Team shared an alert Friday, with officials appealing to the public for help finding the missing pair. Krystal is described as a white woman, 5-foot-7, weighing about 150 pounds, with blonde hair and blue eyes. Alexis is described as a white woman, 6 feet tall, weighing roughly 120 pounds, with black hair.

Investigators are urging anyone with information about their whereabouts to come forward immediately.