Scientists said that a megaflood could happen in California, much as it did during the Great Flood of 1862.

In an unlikely-sounding scenario that has happened before, a new study raises concerns about massive floods brought on by climate change that would dump enormous amounts of water on California's drought-stricken state.

In the West, severe droughts, wildfires, and earthquakes are generally the primary causes of concern, but a study released on Friday warned that "Megafloods" are posing a new threat to California.

It stated that the risk of floods, which could engulf cities and evict millions of people throughout the state, is rising due to climate change. 

It further claimed that hundreds of miles of California could receive feet of rain over the course of a monthlong storm, and in some places more than 100 inches.

The situation may seem like something from a movie, but it has happened before.

Throughout the 20th century, California has seen numerous severe floods, including those in 1969, 1986, and 1997.

Researchers are now looking at the Great Flood of 1862, which occurred much further in the past, as the potential danger to California grows every day.

The flood, which happened 160 years ago but was still considered a "megastorm" due to the state's extensive coverage by historical rainfall, shows that the threat is real and present.

The "megaflood" researchers at UCLA claimed that such storms typically occur every 100 to 200 years.

Researchers are raising the alarm because a flood of that magnitude today would have far more disastrous effects in the most populous state in the country.

Furthermore, a drought occurred before the Great Flood of 1862.

Highlights of the Great Flood of 1862

From Christmas Eve 1861 until January 1862, severe downpours pummeled central California "virtually unabated," according to a 2013 Scientific American article titled "The Coming Megastorms."

According to the magazine, the water flowed into an area at least 300 miles long, creating a massive inland sea that submerged Central and southern California for up to six months.

In a recent study on flood risk, UCLA researchers noted that floodwaters had a 60-mile width.

William Brewer, a scientist, wrote that cattle are starving and drowning on thousands of farms that are entirely underwater.

He added that since there are no passable roads in the state's center, the mail cannot get through. Additionally, the telegraph does not operate completely. The tops of the poles are submerged in water for a considerable distance in the Sacramento Valley.

In a retrospective published earlier this year, the SFGate news site estimated that 4,000 people perished and that one-third of all the state's property was severely damaged, including a quarter of its 800,000 cattle, which either starved or drowned.

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The Great Flood of 1862 vs. Today

Many more people now live in the area that was underwater in 1862; some of California's fastest-growing cities, like Bakersfield and Sacramento, are located there.

The state's population was around 500,000 then, but it is now very close to 40 million.

They claimed that the catastrophe that would result would be the worst disaster in history and would cost approximately $1 trillion in damages.

According to study co-author and UCLA climate scientist Daniel Swain, the effects would extend beyond southern and central California.

He predicted that major thoroughfares like Interstate 80, which slices through California through San Francisco as well as Sacramento, and Interstate 5, which traces the Pacific coast from Canada to Mexico, would likely be closed for weeks or months.

Global supply chains and economics would be impacted by the cascading effects.

Research on possible flood effects and mitigation strategies is ongoing. Because the drought, wildfires, and earthquakes receive all the interest, Swain said it is crucial to keep the issue fresh in Californians' minds.

In California, there is always a chance for serious wildfires, but many years pass without any significant flood news.

Swain pointed out that people forget about it, USA Today reported.

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