DENVER -- Authorities in southeastern Utah are searching for a Colorado woman who hasn't been heard from since Sunday when she went for a hike alone.

Rose Backhaus, 54, of New Castle, Colo., was reported missing when she didn't show up for work at her job in Glenwood Springs on Monday.

An aerial search around Moab, Utah, where she spent Saturday night, failed to turn up any sign of the woman or her vehicle. She was last seen checking out of a local motel on Sunday morning.

A cell phone call to check her messages was traced to a tower in the Four Corners area of New Mexico. That call was made at 10:20 a.m. Sunday and is the last contact with Backhaus that is known.

Her son said she had no connection with New Mexico and the call was likely made from Bluff area of San Juan County, about 100 miles south of Moab.

Authorities are looking for the dark-red 2004 Ford Explorer that Backhaus was driving to help them pinpoint where she might be. The sport utility vehicle has a gray interior and bike rack on the back. It has Colorado license plate 342-JVV.