The parents of a girl killed by a chunk of ice in Snohomish County sued the U.S. Forest Service because warning signs were not posted at the Big Four ice caves, but their lawsuit has been dismissed.

Grace Tam, 11, was posing for a picture in front of the Ice Caves near Verlot in the Mount Baker-Snoqualmie National Forest in July 2010, when a chunk of ice the size of truck fell and killed her.

John Tam said his daughter was 18 feet in front of the opening to the caves and that the sign that warned of the danger was missing.

"It wasn't missing one day or one week; it was missing more than 30 days," he said.

If the sign had been posted, Tam said his family wouldn't have ventured past it and Grace would be alive.

The Forest Service said other signs warning of the danger were posted -- in the parking lot, at the trail head.

The Tams sued the federal government, saying the forest service was negligent in its effort to warn visitors.

"(To) make sure it never happen to other family," said Tamami Okauchi, Grace's mother.

The lawsuit was dismissed last week after government lawyers argued there isn't a federal law that requires them to replace safety signs on a certain schedule.  

"I was really disappointed," Okauchi said. "We are not given chance to bring out the fact that Forest Service didn't follow safety measures,"

The sign was replaced two days after Grace was killed. The Tams think the entire area should be closed off.

The Tams have 60 days to appeal. They haven't decided yet if they will.

The U.S. Forest Service said the incident is tragic, and that "We're sorry for the family's loss."