Brittany Stalman, 17, was reported missing after failing to return from a walk in north Delta on Nov. 13. ((Delta police release))

The parents of a missing Lower Mainland teenager made a public appeal Thursday for help in finding their daughter, who went missing more than a month ago.

Brittany Stalman, 17, left her home in North Delta on Nov. 13 after an argument. She said shewas going for a walk and left her purse and wallet behind.

Sandra Stalman said the family is desperate to find the teen, who hasa history of depression.

"You know, she's got ups and downs no different than any other, but she's basically a happy kid,"Stalman told a news conference at Delta police headquarters.

"And as far as Christmas goes, Christmas is going to be tough without her home. It's going to be hard on the whole family. We just hope we hear something."

Delta police say they have "exhausted all traditional avenues" in their search for thegirl. They say she has run away before, but never for this length of time.

As part of their effort to find Brittany, the Stalmans said, they have hired a private investigator.

The teenwas last seen in the Westview Drive and 64th Avenue area in North Delta near a park.

She is five feet six inches tall, weighs 110 pounds and has long brown hair and brown eyes. When she left home, she was wearing a black jacket, grey sweatpants and was carrying a pink Discman.