When 6.3 mm of rain is too much
A few years ago I passed through the Atacama Desert in Chile, the driest place on earth. Not a blade of grass, not a single shrub, not a single creature, just expanses of dry mountainous valleys. They get rain on one day every decade, roughly.
Yesterday was one of those once-a-decade days, and it wreaked havoc.
A similarly wet stretch in early July dumped four years' worth of rain in one day on coastal Antofogasta. That was just a quarter of an inch (more than 6.3 millimeters) but it was still enough to cause collapsed or leaking roofs in homes and businesses that usually have no reason to protect themselves against even minimal precipitation.
Here's a photo I took near where the Atacama Desert starts: