Authorities are searching for a 78-year-old Oregon man who left his family's home and then called cops to report that he had fallen into a hole.

Thomas Weightman was reported missing at around 5:30 p.m. local time on Tuesday. His family told Forest Grove police he had left their home on foot at around 10 a.m. that day and did not return, according to the Washington County Sheriff's Office.

During a brief phone call, Weightman said he fell into a hole and wasn't sure where he was, police say. Authorities tried to find Weightman using cell phone triangulation, but have been unsuccessful in the remote area.

Sheriff's Office Detective Shannon Wilde said it's been difficult to find Weightman, given the off-the-grid rough terrain.

"Of course, we've used cell phone records...but because this is such a rural area and there's fewer cell towers, that information has not helped us come up with a really narrow search area," Wilde told Fox 12 Oregon.

Wilde described the search area as "very deep terrain with ravines and trees. Obviously, we have some open fields because there's farming property out here. It's a really challenging geographic area."

There are also concerns about the nighttime temperatures this time of year, as Weightman was wearing just a flannel when he went missing. Forest Grove will see lows of about 39 degrees on Friday night.

Search crews have asked locals to check their properties for the elderly man.

Weightman is 5 feet 9 inches tall and weighs 165 pounds. He has gray hair, a gray beard and glasses. The missing man was last seen wearing a red flannel button-up shirt, blue jeans, black shoes and a dark colored baseball hat.

"A lot of the neighbors are out and about," Mark Solar, who lives in the search area, told Fox 12. "I'm sure they're keeping their eyes open when they are out, whether it's a little bit of farmwork they're doing or whatever, I'm sure they're going to be keeping their eyes open."

Forest Grove police urged community members to avoid searching for Weightman on others' properties.

"We know there is a desire for the community to help with searching on foot. Right now, Search and Rescue is asking property owners to search their properties, but are asking that community members avoid the area where they are working," the police department said.

The department also announced that drone teams have been searching for the man for days. Fox 12 reported more than 10 agencies are working on the case, using drones, dogs and foot patrols.

Wilde called the search effort "very overwhelming."

"I think anytime someone goes missing and we're doing this large search effort, it's very overwhelming," Wilde said. "Typically, families are very grateful for the efforts put in, but obviously, the longer this goes on, the more concerning it gets for the family and for us as to what kind of condition he might be in."

Authorities have asked anyone who saw Weightman after 3:30 p.m. on Tuesday to call its non-emergency number at 503-629-0111, and if they have found him, they are advised to call 911.

Missing 78-year-old man called cops to report that he had fallen into a hole