David Himmel, a 16-year-old sophomore from Esperanza High, was killed when his dirt bike collided with a dune buggy at Glamis Dunes in Imperial County.

According to his uncle, Tom Blumberg, David suffered massive chest injuries among other injuries and was killed instantly.

Blumberg said the collision was at a very high speed, and the culpability likely "lies at a 50-50 split." Alcohol or drugs are not likely to have been involved, he said, and it is likely a case of being in the wrong place at the wrong time.

"You almost wish that was the case (being under the influence), so the parents have a place to channel their grief," he said.

Blumberg, a Placentia resident, went out on dirt bikes at Glamis going back about 30 years, and he talked about how the conditions at the dunes have changed drastically since he first started going there.

"Motorcycles now are three times as fast as when I was a kid," he said. "And it's much more crowded than 30 years ago."

Blumberg said David was an expert rider - he has pictures of David doing 40-foot jumps - but suggested he "maybe was almost too experienced."

"If anything this can be a cautionary tale for 16-year-olds who think they're bulletproof," he said.

David, a Yorba Linda resident, is survived by his mother, father and two brothers - one of them a twin, Ryan, also attending Esperanza High School. Ryan shared a few classes with his brother, and going back to school has been particularly tough these first few days.

"I look at his seat, and he's not there," Ryan said. "I know he's not absent. I know he's not sick. I know he's gone forever."

Ryan, who said he "loves dirt bikes more than anything in the world," wasn't sure what getting back on a bike again would be like.

"I don't know if I'll ever be able to ride the same way again," he said.

Lorri Walls, a counselor at Esperanza, said she heard some students were making T-shirts in honor of David, and that he was a well-liked student.

"In general with his friends, he was just a happy upbeat kid," she said.

The family is holding services at Calvary Church in Yorba Linda at 10 a.m. Saturday, and the burial will be at the Forest Lawn in Covina immediately afterward. Blumberg said that in lieu of flowers, the family has set up a trust with the Orange County Teachers Federal Credit Union to help with burial expenses and other financial issues faced by the family.

Speaking of David's father, Blumberg said he's "a hard-working blue collar guy" who did "a lot of sacrificing for his kids."

"This is not only a terrible emotional hardship but kind of a financial one too," Blumberg said of the burial.