Nearly 80 million properties across the country are at risk from wildfires, according to a first-of-its-kind study that tries to calculate how widespread the threat has become for homeowners and businesses across the U.S. as climate change stokes the danger to new levels every year.

Not surprisingly to fire-weary Californians, many of the properties with the highest risk are in the West, including many of the places already well-known for fire danger in the Golden State: The Sierra Nevada foothills and the hilly suburbs in Santa Barbara, Los Angeles, San Diego and other Southern California counties. Much of the Bay Area was listed as low risk, although the hills in the East Bay, particularly around communities like Dublin, San Ramon, Blackhawk, Livermore and Walnut Creek were considered high risk, along with parts of Solano County, like Fairfield and Vacaville.

Until now, quantifying the risk of wildfires has been more difficult than floods, because of their deeply unpredictable nature. Wildfires can spread rapidly, as the wind moves embers and sparks long distances, igniting trees and buildings.

On Monday, nonprofit First Street Foundation released a nationwide wildfire risk assessment — a massive trove of data that will be integrated into Realtor.com, so that prospective buyers can see what the fire risk is for any given property.

“Unfortunately, [until] this point there’s never been a way for people to understand what their wildfire risk is on a property level,” said Matt Eby, founder and executive director of First Street.

First Street found that nearly 80 million properties are at some risk of wildfire, ranging from minor (less than a 1% chance of wildfire damage over 30 years) to extreme (more than 26% chance of wildfire damage over 30 years).

While the vast majority of those properties — 49 million — are at minor risk, more than 4 million are at severe or extreme risk.

Want to know the risk factor for your home? Click here and input your address.

Western states are experiencing drier and hotter weather, which dries out vegetation and creates more fuel for fire. Several destructive fires this year have already ignited well before the hottest, driest months, including a fast-moving blaze last week that destroyed 20 homes in a wealthy Orange County, California, community.

“The hazard is increasing because burn probabilities are going up,” said Dave Sapsis, a wildland fire scientist at Cal Fire. “There’s more fuel. The fuels are highly desiccated because we’re in protracted droughts. There’s also more [property] that’s out there in the way to get impacted.”

Some experts said the new wildfire risk assessment maps should be read with caution and plenty of context.

Craig Clements, director of San Jose State University’s Fire Weather Lab, said he was surprised that Santa Rosa, which has been devastated by wildfires in recent years, was listed as low risk, as were forests around the northern edges of Lake Tahoe and most of the Santa Cruz Mountains, where the CZU Lightning Fire burned more than 86,000 acres two years ago, destroying 1,400 buildings and blackening Big Basin Redwoods State Park.

“Taking climate models down to individual addresses is tricky,” Clements said. “We should take that with a little bit of caution. There are lots of risk models out there. And you can reduce your risk.”

Clements noted that many of California’s largest fires have started from powerlines that sparked or fell during wind storms because PG&E and other utilities hadn’t properly maintained them. Some fires start as a result of freak dry lightning storms, or arson.

Homeowners can make upgrades to their homes, he said — from replacing wood shake shingles with fire-resistant shingles, to clearing brush and thinning vegetation. When many neighbors take such steps, studies show it reduces risk of whole communities by slowing fire spread.

“If you are in a high-risk area it doesn’t necessarily mean you are doomed,” Clements said.

Despite the drumbeat of headlines about wildfires from Colorado to New Mexico to California, the First Street study found the state with the most addresses currently at risk is Florida. But California will vault into the lead over the next 30 years.

The risk also will rise in Southern states such as Texas, as well as in states in the Appalachian region of the country, like West Virginia, Kentucky and Pennsylvania, the study found.

“In Florida and other parts of the Southeast, this kind of climate change looks different than it does out West, but fire is every bit as dangerous,” said Ed Kearns, First Street’s chief data officer.

Six counties in New Mexico — including areas where the Calf Canyon-Hermits Peak Fire has burned more than 280,000 acres in recent weeks — are among the counties with the nation’s highest percentage of properties at risk of wildfire, according to First Street’s models.

In Texas, at least 90% of properties in 45 counties are at some risk.

Dry grass is a key fuel for wildfire in Texas, according to Brad Smith, a wildland fire behavior analyst at the Texas A&M Forest Service. Over 30 percent of the state was in extreme drought in mid-May — a month that is typically the state’s wettest.

“I’ve been working fire for 40 years now,” Smith said. “Homes aren’t saved on the day of the fire; they’re saved days, weeks, years ahead of time. Buying homes, you want to be aware — just like a flood zone — that there are fire zones, too, where homes are more at risk.”

Bay Area News Group Staff Writers Paul Rogers and John Woolfolk and CNN contributed to this story.