The collapse of a sand hole that killed a 7-year-old Indiana girl who was digging with her brother on a Florida beach is an underrecognized danger that kills and injures several children a year around the country. Sloan Mattingly died Tuesday afternoon at Lauderdale-by-the-Sea's beach when a 4-to-5-foot-deep (1-to-1.5-meter) hole collapsed on her and her 9-year-old brother, Maddox. Lauderdale-by-the-Sea, a small enclave north of Fort Lauderdale, does not have lifeguards at its beach, so there were no professionals immediately available to help.