The water was eerily glassy and calm. Then a 16-foot shark attacked from behind, leaving a young surfer desperately trying to defend herself.

"It was weird. I was sitting out there thinking, 'Wow, this feels shark-y to me,"' Megan Halavais (search), 20, said Thursday. "It was straight out of 'Jaws."'

Halavais was paddling into the water off Salmon Creek Beach (search) in Sonoma County in Northern California on Wednesday when the shark attacked. Halavais, an experienced surfer, said she got away after she hit the shark on its tail.

"A 16-foot shark is a big shark. It's not just 16 feet in length. It's big. I couldn't fit my arms around its tail. Its fin, its main dorsal fin, was like taller than me," Halavais recounted for reporters at Santa Rosa Memorial Hospital (search) as she sat in a wheelchair, her bandaged leg extended in front of her.

"I was just paddling. It came from behind. Sharks, if they want to eat you, they don't want you to see them before they eat you," she said.

"I felt a bump hit, I think that's when he bit me. I think I grabbed around -- I was like trying to throw my body on top by his dorsal fin and then grab the tail. I was trying to push. I was just pushing it away."

Halavais, from Santa Rosa, was helped from the water by other surfers. She was taken to a hospital with a bite that stretched from her thigh to her calf. She was listed in good condition.

The beach has been the site of several shark attacks in recent years. Police believe the shark likely was a great white. They have closed the beach and warned surfers in nearby locations.

"The water was really glassy, really calm, really clear like you could see straight to the bottom," Halavais said. "Happy to be alive."