Multnomah County Disaster Risk
Multnomah County, Oregon
FEMA Risk Rating
Relatively High
National Percentile
98th
of 3,144 counties
State Rank
#1
of 36 (1 = highest risk)
Flood Risk
96th
percentile
Hazard Risk Breakdown
Flood
River, coastal, and surface flooding risk
Relatively High
Higher than 96% of US counties
Wildfire
Wildland and wildland-urban interface fire risk
Relatively Low
Higher than 67% of US counties
Tornado
Tornado and severe thunderstorm risk
Relatively Low
Higher than 47% of US counties
Earthquake
Seismic activity and ground shaking risk
Very High
Higher than 100% of US counties
Risk Overview
About Natural Disaster Risk in Multnomah County, Oregon
Multnomah faces higher-than-average disaster risk
Multnomah County's composite risk score of 98.47 and Relatively High rating place it well above the U.S. average. The county confronts a diverse hazard landscape, with particularly acute earthquake (99.59) and flood (95.55) exposure.
Oregon's riskiest county by far
At 98.47, Multnomah County's composite score far exceeds Oregon's 63.43 state average, making it the state's highest-risk county. This reflects Portland's dense urban population, aging infrastructure, and proximity to major fault lines and river systems.
Significantly riskier than surrounding areas
Multnomah's score of 98.47 dwarfs nearby Clackamas (lower risk), Yamhill, and Washington counties. The concentration of people, infrastructure, and hazard exposure in the Portland metro area drives these elevated figures.
Earthquakes and floods dominate Multnomah
Earthquake risk reaches 99.59—among the nation's highest—due to proximity to the Cascadia Subduction Zone and local faults. Flood risk scores 95.55, reflecting the Willamette and Columbia river systems and aging stormwater infrastructure throughout Portland.
Comprehensive coverage is essential
Multnomah residents should carry earthquake insurance (often available as a rider for 10–15% of home value) and verify flood coverage, especially near river corridors and low-lying areas. Wildfire insurance riders also warrant consideration given wildfire risk of 67.30 and smoke exposure during fire season.
Source: FEMA National Risk Index · Narrative reviewed by Evan Brooks, Data Editor
Preparedness Guide
What to Prepare for in Multnomah County
Top Hazards by Exposure
Source: FEMA National Risk Index v1.19.0 · Percentiles are national (3,144 counties)
Risk Advisory: Multnomah County
Risk Verdict
FEMA's National Risk Index places Multnomah County at the 98th percentile nationally — in the high-risk bracket for U.S. counties. Residents should prioritize a formal household emergency plan, including evacuation routes, insurance review, and a well-stocked emergency kit.
Hazard Breakdown
Earthquake risk is Multnomah County's dominant natural hazard, ranked at the 100th percentile nationally under FEMA's National Risk Index. Flood ranks second at the 96th percentile nationally. Additional tracked hazards include wildfire (67th percentile), tornado (47th percentile).
Preparedness Context
Earthquake exposure at the 100th percentile nationally puts Multnomah County in a zone where utilities — gas, water, electrical — are the most common post-quake hazard. Knowing how to shut off the main gas valve is an important household skill to develop before an event occurs. Flood at the 96th percentile nationally is a separate hazard dimension for Multnomah County that requires different protective strategies from earthquake preparedness. Multnomah County households benefit from keeping shoes and a flashlight near the bed — post-earthquake navigation through debris in the dark is a common cause of secondary injury. This low-cost step has outsized protective value.
Regional Context
Multnomah County is 35.0 composite risk points above the Oregon average, indicating that residents face greater natural hazard exposure than most of their in-state neighbors.
Is your household prepared for Multnomah County's hazards?
Review FEMA's county-specific preparedness checklists and emergency planning guides.
Frequently Asked Questions
What is the natural disaster risk in Multnomah County, OR?
What types of natural hazards affect Multnomah County?
How does Multnomah County risk compare to the Oregon average?
Is Multnomah County at risk for earthquake?
How is natural disaster risk measured?
Why is Multnomah County higher risk than average?
Data Source
Risk data sourced from the FEMA National Risk Index (NRI). Risk scores are relative rankings (0–100) across all US counties — not absolute risk measures. Higher scores indicate higher relative risk compared to other counties.
Disclaimer: This data is informational only. It is not financial, insurance, or legal advice. Always consult a qualified professional before making insurance or real estate decisions.