When the Camp Fire raced into Paradise last November, the majority of the people killed were elderly, disabled, or poor – or some combination thereof. Seven months later, many of the community’s poorest residents are living in trailers or temporary housing, with little prospect of moving back to Paradise.

Whether a community’s buildings will succumb is just one part of a wildfire’s saga. People need to evacuate those buildings, and to rebuild (or not) when the fire is over. Will they be able to get out if the town burns again, and what are the challenges in getting them to safety? How will they navigate the slow, difficult, often uncertain process of rebuilding? Will they ever come back at all?

How devastated a community will be by disaster – and how much it will be able to rebuild – is based in part on social factors like residents’ income, age, housing situation, and existing illnesses and disabilities. If fire hazard determines how likely it is that a community will burn, factors like these affect how it will respond.

According to FEMA, adults over 65 had 2.5 times the relative risk of dying in a fire than the general population in 2016. Evidence suggests that people with disabilities are at increased risk during a disaster. And events like wildfires are harder on those dealing with poverty, who may have a harder time evacuating and whose financial straits can be worsened by a disaster.

It’s known as “social vulnerability,” and Direct Relief has increasingly been taking it into account when planning disaster preparation and response.

Building on a recent collaboration among four news services, Direct Relief has mapped which California communities would likely be hardest hit by a wildfire, based on social vulnerability. Direct Relief determined social vulnerability by using five key factors from the CDC’s Social Vulnerability index – poverty, age, disability, vehicle ownership and housing situation. The results can be viewed an interactive map.

This information isn’t just theoretical. Direct Relief has been working to pilot a new facility-based wildfire response pack, containing everything from air purifiers to antibiotic ointment, to be placed in strategic locations near wildfire-vulnerable communities. The organization will take data from the Fire Map into consideration when deciding which communities would most need resources in the event of a fire.

Living in California means living with the ever-present threat of fire. Experts keep saying that “wildfire season” is now year-round. The state suffered its worst year for fires – ever – last year. Three 2018 blazes are on Cal Fire’s list of the top 20 worst California fires since 1932.

As part of an ambitious collaborative project called Destined to Burn, the news services Gannett, McClatchy, Media News, and the Associated Press found that 2.7 million Californians live in what Cal Fire designates “Very High Fire Hazard Severity Zones.” (That means that nearly 7% of the state’s population lives at the highest category of risk from wildfire.)

The project builds on work by Cal Fire (more formally known as the Department of Forestry and Fire Protection), which in 2007 divided the state into “Fire Hazard Severity Zones” based on local topography, vegetation, weather, and fire history, among other criteria. (Cal Fire is currently in the process of developing updated maps.)

The news organizations combined Cal Fire’s mapping with data from the 2010 U.S. Census. Putting the two together made it possible to figure out how much of the population, and how many communities, were at severe risk from wildfire. The analysis found 75 California towns and cities (with populations above 1,000) that were almost fully contained within Very High Fire Hazard Severity Zones.

In its new analysis, Direct Relief looked at all 75 towns and cities, and included people living within five miles of city limits, to figure out which communities were most vulnerable from a social perspective.

There are a lot of potential social-vulnerability factors – everything from living situation to education to health – so the organization just focused on the five that would most directly affect people during and after a wildfire: percentage of people living below the poverty line, percentage of people aged 65 years and older, percentage of housing in structures with 10 or more units, percentage of households with no vehicles, and percentage of people with disabilities living in the larger community.

Each community was given a score for individual social vulnerability factors and an unweighted sum for overall vulnerability.

The interactive map above allows you to examine results for all 75 communities at severe risk from wildfires, to see how their vulnerability is affected by demographics.