VERLOT — A mild winter and warm spring have caused sections of the popular Big Four Mountain Ice Caves to collapse.

Visitors are being urged to stay on the trail and well away from the caves.

The ice is formed by avalanches that roar down the mountain’s north face during winter and spring. Most years, one or more caves form as the ice melts.

“As we head into the busiest and warmest part of the season the cave is in its most dangerous state,” said Matthew Riggen, a lead field ranger for the U.S. Forest Service. “The cave is in a condition that we would normally not see until at least September — large, inviting and collapsing.”

That concerns John Tam and his wife, Tamami Okauchi, whose daughter was killed by a bouncing chunk of ice July 31, 2010, while on a family outing. Grace Tam never went inside the caves. She was sitting on a flat rock about 20 feet from the ice.

Grace remained conscious for more than an hour, but by the time medical help arrived, it was too late. She was 11, loved animals and enjoyed writing poetry and in her journals.

Okauchi remembers the day seemed “very toasty” and the ice on the ground was slushy. The main ice cave appeared rather small and another largely melted cave stood as an arch on the hillside.

She, her children and some visitors were waiting to have their photo taken. Okauchi heard a snap.

“I turned my head to the left to make sure our boys were safe and then to the right to find a boulder-size (piece) of ice fall off and hit Grace and roll over her body,” she said in an email.

She doesn’t want anyone else to lose a loved one.

Last summer, the Marysville couple and the Forest Service installed a plaque with Grace’s image on it along the trail. It is meant to serve as a warning sign to stay away from the caves.

The last paragraph on the plaque describes the danger of the inviting spot: “The Tam family wants you to be aware that this is a beautiful but always changing environment. They hope that you enjoy the ice caves and Big Four Mountain only from a distance.”

On Sunday alone, rangers counted 442 visitors to the trail, which is about 20 miles east of Granite Falls off the Mountain Loop Highway.

Snohomish County Sheriff’s Sgt. Danny Wikstrom, who heads up the department’s search and rescue operations, hopes people will heed the message on the plaque.

“I would ask that in addition to looking at that beautiful mountain, visitors should stop and look at that beautiful marker for a beautiful little girl,” Wikstrom said. “I wouldn’t want anyone else to experience that horrible loss.”

Eric Stevick: 425-339-3446, stevick@heraldnet.com