Portland’s most dangerous climate future is not found in a single wildfire zone, floodplain or heat island. It is concentrated in neighborhoods where several hazards converge—and where decades of economic disinvestment have left residents with fewer resources to prepare, recover and relocate. A new study from Portland State University has produced one of the most detailed maps yet of this overlapping risk, revealing that the city’s most vulnerable communities are largely located in East Portland, particularly near the I-205 corridor. The research shows that exposure to extreme heat, flooding, wildfires and landslides is closely linked to income, education, race, disability, access to hospitals and the availability of natural features such as wetlands.
Published in the journal Natural Hazards, the study examined Portland through a social, ecological and technological systems framework. Rather than treating each natural hazard as an isolated event, researchers analyzed how environmental threats interact with the built environment and with social conditions. The approach recognizes that a neighborhood’s risk is not determined only by whether it lies near a river or on a steep slope. Tree removal, drainage systems, housing patterns, transportation networks, historical zoning decisions and access to emergency services can all alter the consequences of a disaster. “We’re not just people experiencing natural hazards, but we’re in a system that interacts with the natural hazards,” said Justin Huber, a doctoral student in Portland State’s Earth, Environment & Society program and the study’s lead author.
The researchers created spatial assessments at two geographic scales: census block groups and census tracts. Block groups are relatively small statistical areas, generally containing several hundred to a few thousand residents, while census tracts cover larger populations and can reveal broader urban patterns. Using these scales allowed the team to examine both neighborhood-level inequality and citywide differences. Hazard layers for extreme heat, flooding, wildfire and landslides were combined with demographic and environmental data, including median income, educational attainment, racial composition, disability, tree cover, wetlands and the distance to hospitals. The result was a multi-hazard potential map designed to show where several forms of danger may overlap, rather than simply ranking neighborhoods according to one threat at a time.
The geography of individual hazards followed Portland’s distinctive terrain. Flooding and extreme heat were more common in the relatively flat areas of East Portland, where extensive paved surfaces can absorb and retain solar energy while low-lying land is more exposed to high water. Wildfire and landslide potential was concentrated in the hillier western parts of the city, where steep slopes and vegetated terrain create different environmental risks. When the four hazards were analyzed together, however, East Portland emerged as the city’s clearest multi-hazard hotspot. Neighborhoods near I-205 recorded some of the highest combined scores, demonstrating how a place that may not face the greatest risk from any single hazard can become highly vulnerable when threats are superimposed.
The social profile of these hotspots was striking. About 5 percent of Portland’s residents live in neighborhoods classified as facing the highest risk from three or more hazards. The 18 census block groups in this category had lower median incomes and lower educational attainment than the citywide average. They also contained fewer wetlands and were located farther from hospitals, potentially complicating both disaster response and long-term recovery. Residents in these areas were more likely to include people with disabilities, a factor that can make evacuation, access to warning systems and recovery from power outages or extreme temperatures more difficult. In addition, the most exposed neighborhoods had a higher proportion of non-white residents, highlighting the unequal distribution of environmental danger across the city.
The researchers connected this pattern to Portland’s history of redlining and uneven urban investment. Much of East Portland near today’s I-205 was classified as “definitely declining” in 1938 maps created by the Home Owners’ Loan Corporation, a federal program whose lending grades helped institutionalize racial discrimination in housing and finance. Areas marked as undesirable often received less investment in infrastructure, public amenities and economic development for generations. Later redevelopment in historically redlined but lower-risk neighborhoods in North and Northeast Portland contributed to rising housing costs. As those communities became less affordable, many residents were pushed toward East Portland, where housing was often cheaper but exposure to heat and flooding was greater. The movement of people, the researchers argue, is itself part of the hazard system.
This history also helps explain why hazard exposure cannot be reduced simply by building protective infrastructure in the places that currently appear most vulnerable. A new park, flood-control project or transportation improvement may make a neighborhood safer, but it can also increase property values and rents. Without anti-displacement measures, residents who endured years of environmental neglect could be priced out just as conditions begin to improve. Huber cautioned that planners must consider how ecological and technological changes influence where people live. “You don’t want to inadvertently cause people to move,” he said. The warning is increasingly relevant as cities invest in climate adaptation and compete for limited housing in neighborhoods with lower disaster risk.
The findings point toward a different model of urban resilience, one that treats natural infrastructure as part of public safety rather than as a decorative addition. Wetlands, tree canopies and other “blue” and “green” spaces can perform several protective functions at once. Wetlands can store floodwater, reduce downstream flows and support cooler local microclimates. Vegetation can provide shade and lower surface temperatures, although its effects on wildfire and slope stability depend on species, density, moisture and land-management practices. Trees may stabilize soil and reduce landslide potential in some settings, while in others dry or poorly managed vegetation can contribute to fire risk. These interactions illustrate why climate planning requires place-specific analysis rather than a universal solution.
Portland’s Foster Floodplain Natural Area offers an example of the type of intervention the study could help guide. In the Lents neighborhood, the city purchased property from more than 60 homeowners and restored space along Johnson Creek so the waterway could overflow safely and store floodwater. Such projects can reduce flood damage while creating habitat, open space and cooler environments for nearby residents. The new research suggests that similar investments should be prioritized according to combined hazard exposure and social vulnerability, with hospitals, evacuation routes and other critical infrastructure planned to remain functional during multiple simultaneous emergencies. As climate change intensifies heat waves, heavy rainfall and wildfire conditions, a map that shows only one threat at a time may no longer be sufficient.
The Portland study is intended to be replicated in other cities where climate hazards intersect with development pressures and inequality. Its central message is both technical and political: risk is produced by the interaction of natural processes, engineered systems and social decisions. A neighborhood’s vulnerability can rise when heat, flooding or fire converges with inadequate drainage, limited tree cover, distant medical care, low incomes and a history of exclusionary investment. By identifying those intersections before disaster strikes, city officials may be able to target green and blue infrastructure, improve emergency planning and protect residents from displacement. For Portland, the maps make a difficult reality visible: the communities facing the greatest number of hazards are often the same communities that have received the fewest resources to withstand them.
Subject of Research: Multi-hazard climate vulnerability in Portland, Oregon, including extreme heat, flooding, wildfires, landslides, social inequality and urban resilience.
Article Title: Spatial assessment of multi-hazard potential across scales using the social, ecological, and technological systems framework
Web References: https://link.springer.com/article/10.1007/s11069-026-08362-9; https://www.portland.gov/bes/protecting-rivers-streams/ffna; https://sites.google.com/pdx.edu/psunrt/home
References: Huber, Justin, and Heejun Chang. “Spatial assessment of multi-hazard potential across scales using the social, ecological, and technological systems framework.” Natural Hazards. DOI: 10.1007/s11069-026-08362-9.
Image Credits: Justin Huber and Heejun Chang, Portland State University
Keywords: climate change, natural hazards, Portland, Oregon, extreme heat, flooding, wildfires, landslides, environmental justice, redlining, urban resilience, wetlands, disaster planning, social vulnerability, climate adaptation
