Many people enjoy swimming at the beach or engaging in various leisure activities during the hot summer days, including digging holes, with children especially fond of this activity. However, experts warn that digging holes on the beach poses a deadly risk, with the fatality rate even higher than shark attacks, which many people are unaware of.
Professor Stephen P. Leatherman of Florida International University highlighted in an article on The Conversation website that while digging holes on the beach may seem harmless, if the hole is deep enough and collapses, those trapped inside will have a hard time escaping.
Research has shown that more people die from suffocation due to being buried by sand than from shark attacks.
Leatherman recounted a case where a 7-year-old girl and her 9-year-old brother dug a 1.5-meter deep sand hole at Lauderdale-by-the-Sea in Florida this February. They were suddenly buried alive when the sand collapsed. Despite efforts by nearby individuals to rescue them, the girl tragically did not survive.
As a coastal science researcher who has studied beaches for years, Leatherman was called to assist in investigating the cause of the girl’s death. Unfortunately, local firefighters did not arrive until several minutes after the incident, unable to save the girl’s life in time.
Leatherman explained that beaches are made up of sand, with grains typically ranging from 0.06 to 2 millimeters in diameter. The most common sand found on beaches is quartz sand composed of silicon dioxide, except for tropical coastlines where there is coral sand made of calcium carbonate.
The weight of sand depends on its composition. Beaches with pure quartz sand have a lot of white sand, weighing around 90 pounds per cubic foot when dry. Most beaches have different minerals, resulting in a brownish appearance. Minerals that darken the sand are heavier, weighing around 130 pounds per cubic foot when dry.
Dry and loose sand grains form a pile with a slope angle of about 33 degrees, known as the angle of repose. The stability of the sand pile is determined by the friction between each grain.
Sand is more stable when wet because surface tension between water and sand grains holds the pile vertically. Once dry, the sand pile collapses as there is no longer surface tension.
Therefore, when digging a hole on the beach, as long as the sand is wet, it remains stable. Once it dries, the sand hole collapses, filling the trapped space and leaving those inside with no air to breathe.
People caught in avalanches can create an air pocket with their hands since snow is light, but the same cannot be done with collapsing sand.
Rescuing someone from a collapsed sand hole is extremely difficult as sand is heavy and unstable. Firefighters and other professionals usually place wooden planks on the sand hole. This allows them to reach down and remove the sand with tools without exerting direct weight on the edges that could cause further collapse.
If involved in rescuing someone trapped in a collapsed sand hole, the focus should be on exposing the person’s mouth and clearing sand from their chest. Once the person’s mouth is clear, artificial respiration can be performed while others continue to dig out the chest area.
From 1997 to 2007, there were 31 fatal cases of sand hole collapses in the United States, mostly involving children. During the same period, 21 individuals were rescued from collapsed sand holes.
These sand holes typically have diameters ranging from 0.6 to 4.6 meters and depths of 0.6 to 3.7 meters. Digging, creating passages, jumping, or accidentally falling into the hole can trigger collapse.
Leatherman emphasized that sand hole collapses can occur suddenly in seemingly non-dangerous situations for most people. When visiting the beach, it is essential to be mindful of sand holes and promptly fill them in. Even shallow sand holes can pose risks to unsuspecting individuals.
Just on July 18, another sand hole collapse incident occurred at a beach in San Diego, California, involving a 16-year-old girl. She dug a 6-foot deep hole that unexpectedly collapsed, burying her alive. Fortunately, rescue workers dug her out around 15 minutes later, and she was unharmed.
Wyatt Werneth, a national spokesperson for the American Lifeguard Association, previously informed ABC that people are not adequately warned about the dangers of playing with sand on the beach.
Based in Cocoa Beach, Florida, Werneth, who serves as a lifeguard, urges people not to dig sand holes deeper than knee depth at the beach and to avoid entering them.
He advises individuals to educate themselves about potential beach hazards such as sand holes and rip currents before visiting the beach. If a sand hole is dug, it should be filled before leaving.
The most crucial aspect is to level the sand hole, regardless of its depth, even if it’s only the depth of a bucket. “Someone could step in and sprain an ankle. In Florida, this is also dangerous for our marine life.”
By raising awareness about the risks associated with beach sand holes, especially for children, tragic incidents can hopefully be avoided.