CHICAGO (NewsNation) — On Saturday at a state park in southern Utah, a 13-year-old boy was digging a tunnel in the side of a dune when it suddenly collapsed, burying the teenager.

He was found 20 minutes later under more than six feet of sand. The temperature was well over 100 degrees.

While the teen still had a pulse after being rescued, he died one day later.

Park rangers say the dune collapse happened quickly and the death remains under investigation.

In the Northeast, another family is in mourning after a similar accident: an 18-year-old man died while playing with his sister on a New Jersey shore beach Tuesday. The incident happened as he was digging a hole around himself and his 17-year-old sister; the sand collapsed onto them.

Rescue crews were able to save the sister, who was treated on scene.

City officials say the two siblings were using plastic flying discs to dig a 10-foot deep hole before they became buried and trapped.

The family was visiting from Maine.

According to Harvard researcher Bradley Maron, 60% of sand collapses are fatal, CBS reported.

The two families in mourning are still recovering from these unexpected tragedies.

Neither have spoken to the media.