Photo: Justin Sullivan / Getty Images
The recent strange flooding in Death Valley, California, the most planet, could have been just a small sample of what some scientists fear will happen to the state to a much greater degree and with nothing less than catastrophic effects.
A study published on the Science Advances site and broadcast by CNN and other publications aims to alert the population of a potential mega-flood never seen before in this region of the United States, which would cover vast regions of the state of California, devastating cities and affecting millions of inhabitants.
Entitled “Climate Change Is Raising California’s Mega-Flood Risk,” the study was conducted by Xingying Huang and Daniel L. Swain, the latter a climate expert working with UCLA.
“We believe that climate change has already doubled the possibility of an event capable of producing catastrophic flooding, but larger future increases are possible due to continued warming”, say the authors in the study’s introduction.
According to them, the scenario of falling water due to an extreme storm could be up to 400% above historical values in the Sierra Nevada, the mountain range that runs along the eastern side of California and where snow accumulates, which later becomes the water that hydrates large cities.
Atmospheric rivers would cause weeks of torrential rain in California
The study, in summary, says that a series of atmospheric rivers, which are common phenomena in California sustained by water vapor produced the Pacific Ocean, would cause consecutive weeks of torrential rain in the Sierra region.
The water would not be able to turn into snow due to the warmer than normal weather, and would go directly down to the low-lying areas of the state. The most affected area would be the gigantic Central Valley, where entire cities such as Sacramento, Fresno and Bakersfield would be flooded.
The Central Valley, which is key in the agricultural production of the country, would become a true sea within California. But the authors say that Los Angeles and Orange counties, where the largest number of people in the state are concentrated, would also suffer terrible flooding and damage.
The study clarifies that mega-floods have occurred before in California, such as that of 1200-62 that transformed the San Joaquin and Sacramento valleys, with areas left with even 30 feet of water. On that occasion the atmospheric rivers produced rain for 43 days in the Sierra.
Scientists believe that events like this can now occur every 25 a 50 years.
The difference is that now in the state there is a much larger population that would be affected and also that the older temperature in the atmosphere, more rain.
Warming accelerates the frequency of mega-floods
As part of the discussion, the study’s authors say their analysis goes beyond their own recent work to show that climate change is robustly increasing the frequency and magnitude of extremely severe storm sequences capable of causing mega-flooding in California.
Death Valley, the hottest and driest place in the US just saw the 4th 1-in-1,000 year rain event in less than 2 weeks in the US.
3/4 of Death Valley’s annual rainfall fell in 3 hours. pic.twitter.com/0DK6HNNZTq— Colin McCarthy (@US_Stormwatch) August 9, 2022
“Our analysis suggests that the possibility that on the present day (2022) the accumulations of precipitation by 30 historically rare days have already increased substantially and that even modest additional increases in global warming will result in larger increases in probability,” they note.
“Ultimately, one of our goals is not only to understand these events scientifically, but also to help California prepare for them,” says Swain, one of the study authors. “It is a question of when and not if it will happen”.
Read more:
– Flooding in Death Valley, an event that “may occur every thousand years”
– Drought in California: a weekly watering day and thousands of unsown fields
– Scientists believe sea level will rise up to a foot in the US by 2050