POLK COUNTY, TN (WRCB)- Search crews are combing the mountains of the Cherokee National Forest in Polk County looking for a man that has not been seen for nearly a week now.

Last Sunday he was dropped off by a friend to go hiking off Highway 30.

Search and Rescue crews say there are several things working against 47-year-old Lonnie Matheson. Being from Clay County, North Carolina, he is not that familiar with the terrain.

On top of that, his cell phone may be dead and the nights have been very cold.

Hiking through the woods since Sunday, 47-year-old Lonnie Matheson called the Polk County Sheriff's Office Friday afternoon saying he was in trouble.

"He called Polk County Sheriff's Office on a 911 line requesting assistance. He said he was wet, cold, tired, needed some help getting out," says Bradley County Fire Chief Dewey Woody, called in to help with the search.

Matheson also placed a call to his friend who dropped him off earlier that week saying his phone was about to run out of minutes. His family called authorities to report him missing.

"They're about like we are. They don't understand the whole situation. They say he's not familiar with the area, and why he come here, they don't understand," says West Polk Fire & Rescue Captain Ricky Black.

His family says he may be suffering from depression and are very worried about him.

Search crews from Bradley and Polk counties, as well as Cherokee County, North Carolina, have been taking to the ground and the air to look for Matheson.

A ping off of his cell phone indicated he was within 500 yards of the Polk County 4-H Camp. Since then, search crews have been focusing on roughly a five square mile area.

"The terrain is very hilly, it's steep, it's dangerous. There are trees down, logs, you can't always take an ATV," says Woody.

Another major concern besides all the rough terrain, the weather. Once the sun has been going down, it has been getting as low as 29 degrees at night.

"Survival in that, without the proper equipment, is tough," says Woody.

With rain falling this past Thursday, the risk of hypothermia is even greater.

Although Matheson had food and water with him at the beginning of the week, the elements are working against him.

Search crews want the family to know they are not giving up.

"We're going to continue to do everything we can do until there's no other signs that he's here," says Woody.

Matheson is described as being around 5 feet, 10 inches tall, with blue eyes and red hair.

Crews say they plan on being back out again, Sunday.