A 71-year-old Hawaii man was believed to be trimming trees in his backyard in Hilo when an unseen hazard killed him, Big Island Now reports. The man slipped "through a soft area of ground" into a two-foot-wide lava tube and fell 22 feet to his death, according to a police statement. Police were called after the man had not been seen or heard from in several days; they went to the property Monday and found the shaft, with the man unresponsive at the bottom of it. The fire department was called in for a rescue, but he was pronounced dead at a nearby medical center. An autopsy found he died of injuries consistent with falling.
As the National Park Service explains, during long volcanic eruptions, if lava flows for "many hours," it can solidify on the top and sides of the stream. That creates a tube through which liquid lava flows, and after the liquid lava drains from it, a cave is left behind. The Washington Post reports lava tubes are ubiquitous on the Big Island, but it's rare for a person to fall into one. A volcanologist says holes called "skylights" can open in the tubes when "a thin part of the roof collapses," and says the skylight in the victim's yard may have been covered with overgrowth, hiding it. (Read more Hawaii stories.)