A 25-year-old Brigham Young University student was still missing Monday morning after apparently spending Sunday night on Y mountain.

Aaron Steven Lowe, a resident of Provo who is originally from Woodbury, Minn., called his wife on a cellular telephone at 3 p.m. Sunday from the block letter on the mountain east of Provo. He hasn't been heard from since then."As far as we know, he was not planning on spending the night up there," said Provo police spokeswoman Karen Mayne. "He wasn't ready."

Six members of the Provo Police Mountain Rescue Team began looking for Lowe at 5:30 a.m. Monday. Several of Lowe's friends and an airplane owned by the Utah County Sheriff's Office were also participating in the search.

Rescuers planned to call in additional help from the sheriff's search and rescue team Monday, Mayne said.

Lowe was wearing an orange T-shirt and carrying a backpack with a couple of sandwiches when his wife dropped him off near 1900 North and 1500 East in Provo, Mayne said. That was about 2 p.m. Sunday. An hour later, Lowe called his wife to say he had reached the Y and was planning to continue hiking over the mountain.

Lowe was going to call his wife to pick him up later Sunday, but by midnight he had not called so she notified police that Lowe was missing.

Some of Lowe's friends were searching for him Monday morning along a fire road on Provo's east bench.