Portland survival atlas
Multnomah County, Oregon
Portland’s biggest natural hazards are earthquakes, inland flooding and heat waves. In FEMA’s National Risk Index they make up 97% of the natural-hazard risk for Multnomah County, home to nearly all of Portland’s 635,109 residents. FEMA rates the county’s overall risk Relatively High. Here is what to do for each, step by step.
- People
- 635,109 Census estimate, July 1, 2025. No. 28 in the U.S.
- County
- Multnomah County Home to 99.6% of Portland’s residents. FEMA rates counties, not cities.
- Overall risk
- Relatively High Score 98.47 of 100. No. 17 of the 30 largest U.S. cities.
- Expected loss
- $440 million A year, from all 18 natural hazards (FEMA estimate).
- Top 3 hazards
- 97% of the county’s risk comes from these three: Earthquake · Inland flooding · Heat wave.
What to do for Portland’s top hazards
The one rule to remember, then the first steps, word for word from our guides. Each guide lists its sources.
Earthquake
FEMA score 99.58: higher than 99.5% of U.S. counties. Expected loss $326 million a year.
- Drop to your hands and knees.
- Cover your head and neck, under a sturdy table if one is close.
- Hold on until the shaking stops. Don't run outside or stand in a doorway.
Inland flooding
FEMA score 95.54: higher than 95.5% of U.S. counties. Expected loss $91.2 million a year.
- Get to high ground now.
- Never walk, swim or drive into floodwater. 6 inches of moving water can knock you down; 12 inches carries away most cars.
- Car stalls in rising water: get out to higher ground if you safely can. Trapped in fast water: stay inside; if water rises inside, get on the roof.
Heat wave
FEMA score 96.82: higher than 96.8% of U.S. counties. Expected loss $10.0 million a year.
- Use air conditioning, or go to a library, mall or cooling center.
- Heat stroke signs: confusion, slurred speech, collapse; hot, dry or soaked skin; 103°F or higher.
- Call 911.
All 18 natural hazards in Portland, ranked
Ranked by each hazard’s share of Multnomah County’s risk in FEMA’s National Risk Index. The score compares the county with every other U.S. county for that one hazard.
| # | Hazard | Share of risk | FEMA rating | Score | Expected loss a year | The rule |
|---|---|---|---|---|---|---|
| 1 | Earthquake | 74% | Relatively High | 99.58 | $326 million | Drop. Cover. Hold on. |
| 2 | Inland flooding | 21% | Relatively High | 95.54 | $91.2 million | Turn around, don't drown. |
| 3 | Heat wave | 2.3% | Relatively High | 96.82 | $10.0 million | Get somewhere cool. Check on anyone who lives alone. |
| 4 | Cold wave | 1.9% | Relatively High | 90.96 | $8.5 million | One warm room. Never heat with an oven or a grill. |
| 5 | Tornado | 0.3% | Relatively Low | 47.39 | $1.2 million | Lowest floor, interior room, cover your head. |
| 6 | Ice storm | 0.3% | Relatively High | 91.80 | $1.2 million | Stay off the roads. One warm room. |
| 7 | Strong wind | 0.2% | Relatively Moderate | 65.52 | $925,000 | Shelter in an interior room, away from windows. |
| 8 | Winter weather | <0.1% | Relatively High | 85.23 | $309,000 | Stay in your shelter, or stay with your car. |
| 9 | Landslide | <0.1% | Relatively Moderate | 96.91 | $296,000 | Follow local alerts. Leave when officials say so. |
| 10 | Lightning | <0.1% | Relatively Low | 45.76 | $219,000 | When thunder roars, go indoors. |
| 11 | Volcanic activity | <0.1% | Relatively Moderate | 93.48 | $159,000 | Evacuate early. In ashfall, stay in and wear an N95. |
| 12 | Wildfire | <0.1% | Relatively Low | 67.30 | $155,000 | Leave early. Know two ways out. |
| 13 | Coastal flooding | <0.1% | Relatively Low | 43.40 | $43,000 | Run from the water. Hide from the wind. |
| 14 | Hail | <0.1% | Very Low | 1.90 | $3,000 | Large hail coming? Get inside a sturdy building and away from the windows. |
| 15 | Avalanche | <0.1% | Very Low | 18.42 | $31 | Check your local avalanche center before backcountry travel. |
| 16 | Drought | <0.1% | Very Low | 12.53 | $4 | Store water now: 1 gallon per person per day. |
| – | Hurricane | – | Not applicable | – | – | Know your evacuation zone. Told to go? Go early. |
| – | Tsunami | – | Not applicable | – | – | Strong or long shaking near the sea: go high now. |
Source // FEMA National Risk Index v1.20 (December 2025), county 41051. Rules: SOS.city survival guides.
The rest of Portland
Portland also reaches into 2 other counties, which FEMA rates separately.
| County | Portland residents | Overall FEMA rating | Top 3 hazards by share of risk |
|---|---|---|---|
| Washington County | 1,632 (0.3%) | Relatively High (96.02) | Earthquake, Inland flooding, Heat wave |
| Clackamas County | 850 (0.1%) | Relatively High (94.87) | Earthquake, Inland flooding, Cold wave |
How to read these numbers
- Share of risk. For each hazard, FEMA estimates the loss each year to buildings, people and farms, then adjusts it for social vulnerability and community resilience. The county’s overall risk is the sum of all 18, so the share shows how much of it each hazard carries.
- Score. A percentile from 0 to 100. A score of 99.5 means the county’s risk for that hazard is higher than 99.5% of U.S. counties.
- Rating. FEMA sorts counties into five groups, from Very Low to Very High.
- Big places rank high. Expected losses grow with the number of people and buildings exposed, so large urban counties rank high on many hazards. A high rating means plan for it, not that it will happen this year.
- County, not street. These ratings cover the whole county. For flood risk at your address, look it up on the FEMA Flood Map Service Center.
- Multnomah County is rated Relatively Low for social vulnerability and Very High for community resilience. Both feed into its overall rating.
Questions people ask
What natural disasters is Portland most at risk for?
Portland’s biggest natural hazards are earthquakes, inland flooding and heat waves. In FEMA’s National Risk Index they make up 97% of the natural-hazard risk for Multnomah County, home to nearly all of Portland’s 635,109 residents. FEMA rates the county’s overall risk Relatively High.
How does FEMA rate Portland’s overall disaster risk?
FEMA’s National Risk Index rates the overall risk of Multnomah County Relatively High, with a score of 98.47 out of 100. The score is a percentile: Multnomah County’s overall risk is higher than 98.4% of U.S. counties. Expected losses from natural hazards there average $440 million a year.
What should I do first to get ready in Portland?
Write down your top three: earthquakes, inland flooding and heat waves. Turn on Emergency Alerts on every phone and sign up for your county’s alerts. Store water: 1 gallon per person per day for at least 3 days, 2 weeks if you can.
Sources
Every number on this page comes from these public datasets. We check them when we review the page.
- FEMA: National Risk Index data, county table (v1.20, December 2025)
- FEMA: National Risk Index frequently asked questions (December 2025)
- FEMA: National Risk Index for Natural Hazards
- U.S. Census Bureau: City and town population totals, 2020–2025 (Vintage 2025)
- Steps: What to do during an earthquake (SOS.city guide; its sources are listed on the page)
- Steps: What to do in a flood or flash flood (SOS.city guide; its sources are listed on the page)
- Steps: What to do in extreme heat and heat stroke (SOS.city guide; its sources are listed on the page)
General safety information, not medical advice. In an emergency, call 911 and follow local officials.
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