SALT LAKE CITY -- Police are investigating the death of a 2-year-old who apparently fell asleep in a hot car in southern Utah.

The Washington County Sheriff's Office said Monday it happened at a house where several out-of-state families were staying during a family reunion near St. George, where temperatures have been topping 100 degrees.

Investigators say the child likely fell asleep during a ride in a van with several other children on Saturday, and wasn't immediately missed when the group got out of the van.

Police say the child's father discovered the unresponsive toddler after several adults returned from a religious meeting.

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Washington County Sheriff's Lt. David Crouse says the death appears to be an accident.

The child's death marks the 12th in Utah since 1996, CBS affiliate KUTV in Salt Lake City reports.

Fifteen children in the U.S. have died in hot cars this year, according to KidsAndCars.org.

"Our goal is to eliminate these hot car tragedies," director Amber Andreason told KUTV. She said the tragedies are "predictable and preventable."