The state of California might soon be devastated by a mega-storm that produces precipitation at levels only experienced once every 500 to 1,000 years. Experts have named it the ARkStorm, short for Atmospheric River 1000, to signify that it is a one in a thousand-year mega event.
According to a report by the U.S. Army Corps of Engineers, floods resulting from the storm could displace more than 1.5 million people in Los Angeles. According to the U.S. Geological Survey (USGS), the ARkStorm could end up causing damage to the tune of US$725 billion statewide. Thousands of square miles of agricultural and urban land could be flooded. This would result in numerous landslides and a complete disruption of lifelines throughout the entire state for several weeks.
“The historical data suggests that such a storm would be fueled by an ‘atmospheric river’ — that’s what the ‘AR’ in ARkStorm stands for — a huge stream of water vapor that floats a mile above the Earth’s surface. After these rivers of water vapor are generated over the warm, moist Pacific Ocean, they travel across the globe, causing severe flooding — and especially so on America’s West Coast,” according to Inverse. The ARkStorm need not be a single storm. Instead, it could be a series of storms that could have a cumulatively destructive effect on the region.
The last time a storm of this magnitude hit California was in December 1861. Intense storms lashed the state for a period of 45 days. Hundreds of people and tens of thousands of cattle were killed in the storms. Los Angeles received a record 36 inches of rain. Sacramento essentially became an inland sea, while the Central Valley could only be crossed by boat. The government of California had to temporarily shift to San Francisco. Neighboring states like Oregon, Nevada, Arizona, and Utah also saw massive flooding.
Though it cannot be predicted exactly when the storm will hit California, experts confirm that it is “plausible, perhaps inevitable.” “A newer study suggests the chances of seeing another flood of that magnitude over the next 40 years are about 50-50,” Daniel Swain, a UCLA climate scientist, said to the Los Angeles Times.
Research into geologic records of the region has shown that six storms with the same intensity as the 1861 one have occurred in California over the past 1,800 years. The USGS has warned the state to update its infrastructure. The U.S. Army Corps of Engineers called for US$600 million from the federal government to upgrade the Whittier Narrows Dam since the structure could fail if hit by an ARkStorm.
Fresno County has already begun work to ensure that they are in a position to deal with the mega-storm when it hits. Friant Dam, Millerton Lake, and the canal systems are said to be in good enough condition to take care of serious storms.
“We’ve checked all records, the one hundred years, and it says the largest 48-hour storm on record, a two-day storm, is about three inches of rain. So if we have that capacity in the basin, we think we are at least prepared for the largest 48-hour storm. If it continues to rain, then yeah, we might look to have some problems,” Alan Hofmann, General Manager of the Metropolitan Flood Control District, said to ABC 30.
Since the district has extensive ponding basins and pumps, they provide an excellent margin of safety for the residents in the region.