Scientists have warned that California's economy could be wiped out in a matter of weeks by a “megaflood” as extreme weather patterns become more common.
Devastating floods have already impacted Bangladesh, Pakistan and South Africa this year, with warming temperatures dramatically increasing the chances of a catastrophic “megaflood”.
New scientific modelling warns that the odds of such an event devastating California has increased from one in 100 to one in 50.
Should climate change increase global temperatures by another one degree Celsius, as scientists believe it might, the annual chances of a “megaflood” hitting the US state increases to almost one in 30.
Daniel Swan, a climate scientist at the University of California, told The Telegraph : “We’re talking about a long series, three to four weeks, of strong winter storms. A megastorm sequence that could potentially result in the megaflood – a particularly severe and widespread flood.
“You would have rivers flowing under major boulevards, under apartments, through movie studios – every part of the state is at considerable risk.”
Such an occurrence would leave towns damaged beyond repair, forcing mass resettlements, while transport networks would be destroyed.
Xingying Huang, from the National Centre for Atmospheric Research in Boulder, explained that a megaflood entailed a rapid procession of “atmospheric rivers”.
This would be different from the current flooding in Pakistan.
A California megaflood would see atmospheric currents funnel water vapour towards the west coast.
As mountains force the currents upwards, the cooling would lead to deluges of rain and snow, with warmer air causing more “intense and insidious” precipitation.
Scientists estimate that the worst-hit area of California could experience over eight feet of rainfall within a month under such circumstances.
“It would severely disrupt all sectors of the economy, tourism, Silicon Valley, the movie industry would all be put on hold for an extended period of time,” Dr Swain said.
While such an event would be highly disruptive, the authors of the paper believe that there would be enough warning time to evacuate.
The study, titled ‘ARkStorm 2.0: Climate change is increasing the risk of a California megaflood’, has been motivated by California’s great flood of 1862.
Dr Huang added that California is not the only place at risk, calling it “a global situation”.
Flooding disasters have been a regular feature of 2022, with 448 people dying in South Africa in April when flooding led to landslides.
Over 1,100 people have died in Pakistan since June as a result of ongoing floods that have affected vast swathes of the country – something which nation states may have to get used to, according to the report.
However, the authors said that potential solutions do exist. Floodplain restoration would reduce risk to urban communities and work is planned with stakeholders to develop disaster resilience infrastructure.
