In the 1950s and 1960s, bunkers were a feature of many American suburban homes, populated by families fearful of the prospect of nuclear war. That threat has subsided, but now many reasonable people are stocking up on essential supplies in preparation for a new cataclysm.
Alex Steffen, a journalist and editor based in Seattle, is one of those "daring to prepare" for a coming "tiny apocalypse".
"The systems we rely on are brittle and facing strain," he says. "Here in Seattle we are vulnerable to earthquakes and I also live near a big volcano. Climate change is causing more extreme weather events. There could be a global bird flu outbreak or some other pandemic."
For these reasons, Steffen and his girlfriend have stocked six weeks' worth of food in their basement and have invested in a water-purifying kit. "We are taking precautions," he says, referring to himself as an "urban liberal survivalist".