struggled to save a 17-year-old buried alive. after digging a pit six feet deep. the sand caved in, trapping matt myna for nearly half an hour. relax, relax. reporter: until, at last, they pulled him out. i couldn t tell if anybody heard me screaming help. reporter: a cautionary tale for anyone headed to the beach this summer. if you re a parent you probably tend to breathe a bit easier when your kid s building sand castles because you figure the sand has got to be safer than the surf. turns out that might not be the se. even a small beach hole can be dangerous for little kids. the danger from shifting sands. a few minutes is all it takes to suffocate someone. a recent harvard study documented more than 50 cases in the past decade. nearly half of them fatal. the number of sand wall collapses was greater than that of unprovoked shark attacks. reporter: it s such a serious risk some communities are banning deep beach holes altogether. myrtle beach in south carolina s
after digging a pit six feet deep. the sand caved in, trapping matt myra for nearly half an hour. relax, relax. reporter: until, at last, they pulled him out. i couldn t tell if anybody hehed me screaming help. reporter: a cautionary tale for anyone headed to the beach this summer. if you re a parent you probably tend to breathe a bit easier when your kid s building sand castles because you figure the sand has got to be safer than the surf. turns out that might not be the case. even a small beach hole can be dangerous for little kids. the danger from shifting sands. a few minutes is all it takes to suffocate someone. a recent harvard study documented more than 50 cases in the past decade. nearly half of them fatal. the number of sand wall collapses was greater than that of unprovoked shark attacks. reporter: it s such a serious risk some communities are banning deep beach holes altogether. myrtle beach in south carolina s already done it. los angeles county may soon follow