Devastating mudslides and flooding are likely to become the number one risk for California homeowners in the next 25 years, outgrowing the threat posed by wildfires, according to a new study by CoreLogic.

By 2050, the company calculated, homes in Los Angeles, San Diego and San Francisco will have a higher flood risk than wildfire risk, forcing their owners to purchase costly extra insurance to protect their properties and equity.

Why It Matters

Climate change is exacerbating the risk of more frequent and more severe natural disasters across the U.S. and posing new challenges to the country’s home insurance market. Private insurers want to price their rates taking into account higher costs and growing catastrophe exposure, while regulators are trying to satisfy their rate hike requests while also keeping premiums affordable for homeowners.

But in some of the most disaster-prone areas of the country, including the Golden State, problems are piling up. In Southern California, the same areas ravaged by wildfires in January were hit by flooding last month.

These are also the neighborhoods where private insurers cut hundreds of policies last year, and where finding coverage is becoming increasingly difficult.

What To Know

According to data from The Nature Conservancy, 8.8 million acres in California are at risk from flooding—the equivalent of about 16 percent of its urban and suburban development, and 36 percent of its land dedicated to cultivated crops. That is not as bad as other U.S. states.

“While wildfire risk, drought and heat waves may be more prevalent in Western states like California, across the U.S. flooding is the most frequent and costly natural disaster in the United States,” Talley Burley, manager in Climate Risk & Insurance at the New York-based organization Environmental Defense Fund (EDF), told Newsweek.

“Where it can rain, it can flood,” Burley said, adding that wildfires, which are common in California, are actually making the state more vulnerable to disastrous flooding.

“The impacts from wildfires can alter the landscape and make floods more common,” she explained. “Wildfires burn vegetation that is critical to absorbing rainfall and reducing runoff. Until vegetation is restored, burned areas increase the likelihood of flash floods and mudslides.

“These impacts mean that even areas not traditionally considered at high risk of flooding may face a greater flood risk as a result of the impacts and changes caused to the landscape by a fire.”

The recent wildfires in Los Angeles County destroyed critical vegetation absorbing rainfall and preventing floods and mudslides, paving the way for an atmospheric river in February to once again devastate the area.

The phenomenon is likely to continue and become much worse in the coming decades, according to CoreLogic, making flooding the biggest risk facing California homeowners.

The company calculated that more than 1 million homes in Los Angeles, San Diego and San Francisco that are currently facing low flood risk will see their flood risk increase by 40 points or more by 2050, according to CoreLogic’s Risk Score.

At the moment, 762,000 homes in Los Angeles, 231,000 in San Diego and 65,000 in San Francisco are impacted by flood risk. In Los Angeles, CoreLogic estimated a current flood risk of 9 points, which is expected to go up to 14 by 2030 and 58 points by 2050.

In San Diego, the company estimated a current flood risk of 9 points, set to go up to 13 by 2030 and 53 by 2050. In San Francisco, the current flood risk is 8 points but is expected to rise to 14 by 2030 and 53 by 2050.

The score goes from one, very low, to 100, extreme. A score between 36 and 55 signals moderate property damage and losses, while between 56 and 70 indicates high property damage and losses.

Californians Are Not Ready

Flood damage is not covered by traditional homeowners insurance or renters insurance policies, and few private flood insurance options are available.

Instead, residents of communities participating in the Federal Emergency Management Agency’s (FEMA) National Flood Insurance Program (NFIP) can purchase flood insurance through the agency.

Properties in areas shown on FEMA’s flood maps as being at high-risk are required to purchase flood insurance if they have a federally-backed mortgage or if the property has ever received federal disaster assistance, Burley explained.

For properties outside of these areas, flood insurance is voluntary.

“Climate change is driving more frequent and intense climate related events, such as flooding,” Burley said. “This is causing not just more deadly and significant hurricanes and coastal storm surges, but also an increasing intensity of heavy rainfall. Heavy rain storms can cause flash floods and urban flooding in areas with limited drainage and low-lying areas are often most susceptible to flood events.”

Precipitation-based flood risk is not currently shown on FEMA’s flood maps, and neither is the added risk posed by wildfires, which increase the likelihood of flooding during storms.

“It’s important to remember that while flood insurance requirements are based on the FEMA flood maps, floods do not follow lines on a map and the FEMA flood maps do not account for all types of flood risk and do not account for growing risk as a result of climate change,” she said.

Californians, who are now waking up to the rising issue of flooding, are not ready for this new challenge. Less than 2 percent of California homes are insured against flood, Politico reported, despite it being widely available on the state’s market.

That might have something to do with the fact that flood insurance is not required for federally backed mortgages in the state, unlike fire insurance, as Burley suggested.

What Happens Next

Flooding can cause billions of dollars in damages—and flood insurance is likely to become even more expensive for California homeowners in areas poised to become more vulnerable in the near future.

FEMA estimates that one inch of water can cause as much as $25,000 in damages, “which means that even relatively minor events can have significant financial impacts,” Burley said.

While homeowners who cannot get coverage in the private market can always rely on FEMA’s NFIP, even these rates are becoming more expensive, especially in high flood risk areas.

Rob Bhatt, an insurance analyst for LendingTree, told Politico that an average NFIP policy is about $866 annually, or $72 per month.

“Growing flood risk may cause the cost of flood insurance to rise overtime,” Burley said. “Flood insurance is required for properties in high flood-risk areas on FEMA’s flood maps if they have a federal backed mortgage or if they’ve ever received federal disaster assistance.”

Rising insurance costs could strain housing affordability and accessibility for all homeowners, Burley said, while making recovery from climate-related events even more difficult for those without coverage.

“Because flood damage is not covered by traditional homeowners or renters insurance, without flood insurance coverage a household that experiences a flood event may have to pay for damages out-of-pocket or rely on federal disaster assistance, which is not guaranteed and can take months to reach impacted households,” she said.