Multnomah County, Oregon Natural Disaster Risk
FEMA National Risk Index assessment · OR
HighComposite Risk Score
National percentile: 98th
Multnomah County faces high composite natural disaster risk (NRI Risk Index score 98.5, 98th national percentile), driven primarily by earthquake and landslide exposure. Expected annual loss across all 18 hazard types is $440M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in Multnomah County is high, with a National Risk Index score of 98.5 out of 100 — placing it in the 98th national percentile and in the upper tier of natural-disaster risk nationally. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
Risk here concentrates in earthquake (ground shaking from sudden movement along geologic faults) at High risk — $326M in expected annual loss and about 0.02 events per year; landslide (downhill movement of rock, soil, and debris on unstable slopes) at Medium risk — $296K in expected annual loss and about 2.05 events per year; and heat wave (prolonged periods of extreme heat that threaten health and infrastructure) at High risk — $10M in expected annual loss and about 6.34 events per year. Across all hazards, FEMA estimates $440M in expected annual loss for a population of 814K.
Beyond physical exposure, Multnomah County has a low social vulnerability rating (how susceptible the population is to harm) and a very high community resilience rating (its capacity to prepare for and recover from disasters). A less vulnerable population paired with strong resilience helps the community absorb and recover from events.
The county's disaster history tells the same story: Multnomah County has received 12 federal disaster declarations since 1964, including 4 for severe storm events and 3 for flood events. The most recent was Severe Winter Storms, Straight-Line Winds, Landslides, and Mudslides (severe storm), declared in April 2024.
Among 36 Oregon counties, Multnomah County ranks #1 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Earthquake | High | 0.02 / yr | $326M |
| Landslide | Medium | 2.05 / yr | $296K |
| Heat Wave | High | 6.34 / yr | $10M |
| Riverine Flood | High | 0.39 / yr | $91M |
| Volcanic Activity | Medium | 0.01 / yr | $159K |
| Ice Storm | High | 1.61 / yr | $1M |
| Cold Wave | High | 0.32 / yr | $9M |
| Winter Weather | High | 16.35 / yr | $309K |
| Wildfire | Low | 0.00 / yr | $155K |
| Strong Wind | Medium | 0.07 / yr | $925K |
| Tornado | Low | 0.04 / yr | $1M |
| Lightning | Low | 7.96 / yr | $219K |
| Coastal Flood | Low | 0.29 / yr | $43K |
| Avalanche | Very Low | 0.01 / yr | $31 |
| Drought | Very Low | 1.87 / yr | $4 |
| Hail | Very Low | 0.08 / yr | $3K |
| Hurricane | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
Disaster History
Multnomah County has received 12 federal disaster declarations since 1964, most recently Severe Winter Storms, Straight-Line Winds, Landslides, and Mudslides in April 2024. Most frequent causes: Severe Storm (4), Flood (3), Fire (2).
| Declared | Type | Disaster |
|---|---|---|
| April 2024 | Severe Storm | Severe Winter Storms, Straight-Line Winds, Landslides, and Mudslides |
| September 2020 | Fire | Wildfires and Straight-Line Winds |
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| September 2017 | Fire | Eagle Creek Fire |
| February 2016 | Severe Storm | Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides |
| March 2009 | Severe Storm | Severe Winter Storm, Record and Near Record Snow |
| September 2005 | Coastal Storm | Hurricane Katrina Evacuation |
| February 2004 | Severe Storm | Severe Winter Storms |
| February 1996 | Flood | High Winds, Severe Storms and Flooding |
Showing the 10 most recent of 12 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Multnomah County?
Multnomah County has a composite FEMA National Risk Index score of 98.5 out of 100, placing it in the High category and the 98th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Multnomah County?
The three highest-rated hazards are Earthquake (High, $326M EAL), Landslide (Medium, $296K EAL), Heat Wave (High, $10M EAL). These account for most of the county's expected annual losses.
How does Multnomah County compare to other Oregon counties?
Multnomah County ranks #1 of 36 Oregon counties for overall natural disaster risk, with a high rating.
How many federally declared disasters has Multnomah County had?
FEMA records 12 federal disaster declarations for Multnomah County since 1964, most often 4 for severe storm events and 3 for flood events. The most recent was Severe Winter Storms, Straight-Line Winds, Landslides, and Mudslides, declared in April 2024.
What does Expected Annual Loss (EAL) mean?
EAL is FEMA's estimate of average annual dollar losses from natural hazards, calculated from historical event data and exposure models. Multnomah County's $440M EAL is a statistical average, not a guarantee for any specific year or address.