Firefighters are calling an Edmonton woman a heroine after she jumped into the fast moving waters of the North Saskatchewan River Thursday to rescue a near-drowning teenager.

Krista Girvan was walking by the river around 2 p.m. when she saw a young woman struggling to stay afloat in the river.

Girvan, a nursing student and trained lifeguard, quickly jumped into the river.

"She started to go under and ... you can't just let someone go under," she said.

A friend of the victim tells CTV News the two were walking along the river near the Capilano Bridge when her friend slipped.

"She fell over and she couldn't get back out," she said.

The friend then tried to help her by jumping in and holding onto a tree branch, but she couldn't reach the teen.

Girvan and her sister-in-law were hiking nearby when they heard the two screaming.

"I swam out to her and I followed the current and I beat her to the middle of the stream and then I just grabbed her from behind and kicked my way back," she said.

Firefighters met then pair in a boat as Girvan was bringing the teen back to shore. Paramedics were waiting for both people on the river bank.

Capt. David Bosch said the quick-thinking passerby likely saved the young woman's life.

"Our reports were that she was starting to struggle and starting to scream for help and once you tire and start to go down ... I think she may have prevented a tragedy there," he said.

Officials from Edmonton Fire Services said Girvan will receive a congratulatory message from the fire chief for her actions.

The department is also considering nominating her for a life-saving award.

Lindsay Bracken, Girvan's sister-in-law, said her relative deserves all the praise soon to be coming her way.

"She's an amazing girl, she's a hero and not just anyone would to that and I'm very proud of her," she said.

The teen took in some water, was tired and shaken, but is expected to be okay.