A 1,000-year flood that rearranged boulders and buckled roads in Death Valley is the latest chilling window into how poorly prepared California is for the now-inevitable El Niño storms.

The same October weather system that stranded 200 cars in mudslides, swamped the desert national park that’s usually one of the driest places in the country. Death Valley usually only gets about four inches of rain per year. One storm dropped three inches of rain in five hours.

How much water swept through canyons which are normally dry this time of year? According to a report in the Los Angeles Times, about 93,000 cubic feet per second was flowing out of Grapevine Canyon, “10 times that of a 100-year flood.” The terms 100-year flood or 1000-year flood are a way of measuring the size of a flood as related to statistical occurrence in any given year. A 1000-year flood has a .1 percent chance of happening.