Biblical flooding brought on by climate change could force millions of people to relocate and drown parts of Los Angeles and Sacramento.
A recent research found that Californians are at danger from a catastrophic flood that could cost $1 trillion in damage, evict millions of people, and submerge parts of Los Angeles and Sacramento.
Climate change has increased the likelihood of biblical floods in The Golden State by a factor of two, according to researchers at the University of California, Los Angeles.
The chances and size of the next megaflood "are bigger in practically every regard" as the Earth heats, said co-author and UCLA climate scientist Daniel Swain.
He reported that there is more rain overall, more intense rain every hour, and greater winds.
the UCLA scientists found that huge areas of California might get several feet of rain during a strong month-long storm like the one that flooded modern Los Angeles in 1862 and buried Sacramento.
A study that was published on Friday in the journal Science Advances suggests that it is possible for some cities to experience more than 100 inches of rain,
which would force 5 to 10 million people to relocate, close the state's roads for a few weeks or even a month, and negatively affect the global economy.
Every century or two, California has experienced such extreme flooding throughout the previous millennia.
Prior to the state investing in flood mitigation strategies, the Great Flood of 1862 measured up to 300 miles in length and 60 miles in width.
The ARkStorm scenario is now expanded in this new study to include the effects of climate change.
The "atmospheric rivers" of moisture that could cause a deluge of biblical proportions are the inspiration for the name of the ARkStorm scenario.
Using high resolution weather models and current climate models, they evaluated two scenarios, one based on the actual climate of recent decades and the other in the anticipated climate of 2081 to 2100.
The scientists found that in both cases, a long line of storms fueled by these atmospheric rivers, which extend thousands of kilometres from the tropics to the western United States, may cause serious damage.
According to earlier research, climate change would cause these atmospheric rivers to warm, increasing storm frequency and intensity.
The analysis came to the conclusion that a flood equivalent to the one that occurred in 1862 would submerge parts of cities like Sacramento,
Fresno, and Los Angeles even with the extensive network of reservoirs, levees, and bypasses in place today.
It would cost $1 trillion and be the biggest tragedy in human history, according to estimates.
Even more concerningly, the initial ARkStorm study found that it would be impossible to evacuate the 5 to 10 million
inhabitants of these places, even given weeks' worth of notice from meteorologists and climatologists.
Using the data from this new study, researchers and state officials are currently working to react to such a significant storm.
They intend to identify probable flood zones and test state-of-the-art flood simulations, which are supported by the California
Department of Water Resources, the Federal Emergency Management Agency, and the California Office of Emergency Services.
The researchers and the government would then use the information to recommend actions to lessen such a severe storm. In order to do that,
it may be necessary to proactively release water from reservoirs, permit floodwater to fill designated floodplains, and steer water away from heavily populated regions.