Rowe said he has been told the boy has vital signs, but he does not know his condition. Officials did not immediately release the name of the boy or where he was from.
The boy's family called 911 about 4:30 p.m. Central time saying their son became covered when they tried to dig him out. Emergency crews were on scene within 15 minutes and began digging by hand, Rowe said. Rowe said he doesn't know what the boy was doing when he initially got stuck, but called the incident "baffling."
"I have never heard of anything like this here or at other sand dune parks," said Rowe, who has worked at the lakeshore since 1991. "I've never heard of anything like this on a sand dune."
Mount Baldy will remain closed during the weekend while authorities investigate what happened, Rowe said.
"We won't let people on the dune again until we know what happened and whether it is safe for them," he said.