Maricopa County, Arizona: Natural Disaster Risk and History
Maricopa County, Arizona has a Very High natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 99.9 out of 100, higher than about 99% of US counties, with heat waves, inland (river and flash) flooding and wildfires scoring highest of its 18 hazards and $2.2 billion a year in expected losses.
OpenFEMA lists 24 federal disaster declarations that included Maricopa County since 1966, not counting 2 for COVID-19; the latest is FM-5501-AZ (Boulder View Fire, declared 28 June 2024). NOAA's Storm Prediction Center recorded 75 tornadoes touching Maricopa County from 1950 to 2025.
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Population 4,418,836 Buildings worth $855 billion Area 9,319 sq mi Risk rank in Arizona 1 of 15 FIPS 04013
All 18 hazards, highest risk first
FEMA National Risk Index| Hazard | Risk rating | Score | Expected loss a year | How often | Events in record |
|---|---|---|---|---|---|
| Heat wave | Very High | 100.0 | $958 million | about 2 a year | 154 |
| Inland flooding | Very High | 99.9 | $1.1 billion | about 8.5 a year | 237 |
| Wildfire | Relatively High | 99.6 | $42 million | about once every 535 years | — |
| Hail | Very High | 99.5 | $24 million | about once every 3.6 years | 11 |
| Strong wind | Very High | 99.1 | $8.8 million | about 1.4 a year | 54 |
| Drought | Relatively High | 97.7 | $4.6 million | about 63 a year | 2,905 |
| Earthquake | Relatively Moderate | 96.8 | $31 million | about once every 93 years | — |
| Lightning | Relatively High | 95.5 | $2.1 million | about 32 a year | 2,141,342 strikes |
| Tornado | Relatively Moderate | 84.0 | $5.4 million | about once every 1.8 years | 36 |
| Landslide | Relatively Low | 83.9 | $28,124 | about 2.1 a year | — |
| Winter weather | Relatively Low | 38.7 | $47,011 | about once every 1.8 years | 11 |
| Avalanche | Very Low | 32.9 | $144 | about once every 100 years | 0 |
| Hurricane | Very Low | 26.6 | $11,770 | about once every 87 years | 3 |
| Cold wave | No Rating | 0.0 | — | — | 0 |
| Coastal flooding | Not Applicable | — | — | — | — |
| Ice storm | Not Applicable | — | — | — | — |
| Tsunami | Not Applicable | — | — | — | — |
| Volcanic activity | Not Applicable | — | — | — | — |
Score: FEMA's percentile among US counties that face the hazard (higher = more risk). Expected loss: FEMA's modelled average yearly loss to buildings, people (as a statistical value) and crops. How often: FEMA's annualised frequency of the hazard in the county; for some hazards it counts event-days, so it is a rough guide, not a forecast. "Not Applicable" means FEMA does not model that hazard here.
Federal disaster declarations 24
Most common: Fire 11, Flood 9, Severe Storm 3, Hurricane 1.
| Decade | Declarations | Incident types |
|---|---|---|
| 1960s | 1 | Flood |
| 1970s | 4 | Flood ×4 |
| 1980s | 1 | Flood |
| 1990s | 3 | Flood ×2, Severe Storm |
| 2000s | 6 | Fire ×3, Severe Storm ×2, Hurricane |
| 2010s | 1 | Flood |
| 2020s | 8 | Fire ×8 |
The last 10
Widest declarations that included Maricopa County
- Hurricane Katrina Evacuation (2005, EM-3241-AZ): 15 Arizona counties designated.
- Severe Storms, Tornadoes & Flooding (1993, DR-977-AZ): 13 Arizona counties designated.
- Severe Storms & Flooding (1978, DR-551-AZ): 10 Arizona counties designated.
Named storms in its declarations: Hurricane Katrina (2005).
Not counted above: 2 COVID-19 ("Biological") declarations — in 2020 every US county was included. Arizona also had 27 statewide declarations with no county list.
Tornado record since 1950 75
| Tornadoes touching the county | 75 |
|---|---|
| Strongest-rated | (E)F3 ×1 |
| Peak month | July (12) |
| Deadliest | 30 Aug 1971, F2, 4.7 mi path, 0 killed, 41 injured |
| Longest path | 1 Sep 1971, F1, 32.4 mi path |
| Most recent | 18 Nov 2025, EF0, 1.1 mi path |
| Deaths / injuries on those paths | 0 / 58 |
| Rating | (E)F0 | (E)F1 | (E)F2 | (E)F3 | (E)F4 | (E)F5 | Unrated |
|---|---|---|---|---|---|---|---|
| Count | 41 | 25 | 6 | 1 | 0 | 0 | 2 |
| Decade | 1950s | 1960s | 1970s | 1980s | 1990s | 2000s | 2010s | 2020s |
|---|---|---|---|---|---|---|---|---|
| Count | 8 | 9 | 18 | 8 | 15 | 1 | 12 | 4 |
Deaths and injuries are for each tornado's whole path, which can run beyond this county. F-scale ratings before February 2007, Enhanced Fujita (EF) after.
How Maricopa County compares with its 5 nearest counties
| County | Distance | Overall risk | Score | Top hazard |
|---|---|---|---|---|
| Maricopa County (this page) | — | Very High | 99.9 | Heat wave |
| Pinal County | 118 km | Relatively Moderate | 93.8 | Heat wave |
| Yavapai County | 139 km | Relatively Moderate | 93.7 | Wildfire |
| La Paz County | 144 km | Relatively Moderate | 83.5 | Inland flooding |
| Yuma County | 147 km | Relatively Moderate | 92.6 | Earthquake |
| Pima County | 154 km | Relatively High | 99.1 | Heat wave |
Nearest by distance between county centres. Every county in Arizona, ranked.
Vulnerability and resilience
| Social vulnerability | Relatively Low 27.1 |
|---|---|
| Community resilience | Very Low 18.0 |
| Community risk factor | 0.97 |
| Expected annual loss, all hazards | $2.2 billion |
FEMA scales expected losses up where social vulnerability is high (people who may find it harder to prepare, evacuate or recover) and down where community resilience is high. A factor above 1 raises the risk score. For social vulnerability a high rating is worse; for resilience a high rating is better.
Prepare for Maricopa County's main hazards
- Right now: National Weather Service alerts for Arizona · all official warnings on Global Incident Tracker.
- Heat wave: Heatstroke warning signs
- Inland flooding: Flood safety: why shallow water kills · Floods recorded
- Wildfire: US wildfires now · Wildfire smoke: what protects you
- Your property's flood zone: FEMA Flood Map Service Center ↗ — this page cannot tell you that.
- Official preparedness guidance: Ready.gov ↗ and your county emergency management office.
What this page shows, and what it misses
FEMA's National Risk Index rates a whole county against every other US county; it is a planning-level estimate for nationwide comparison, not a flood-zone map and not a substitute for a local risk assessment or the risk to one home. Declarations are presidential disaster, emergency and fire management declarations that named this county; state declarations and SBA or USDA designations are not included. Tornadoes are counted when the county is one of up to four listed on the track; 670 tornadoes that crossed a state line carry no county list in NOAA's file and are left out.
Federal Emergency Management Agency (FEMA), National Risk Index Dataset: National Risk Index Counties - v1.20.0 (December 2025). Retrieved from https://services.arcgis.com/XG15cJAlne2vxtgt/ArcGIS/rest/services/National_Risk_Index_Counties/FeatureServer/0/query on November 2, 2026, 1:20 PM EST. This product uses the Federal Emergency Management Agency’s National Risk Index dataset API or downloadable datasets but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
Federal Emergency Management Agency (FEMA), OpenFEMA Dataset: Disaster Declarations Summaries - v2, retrieved from https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries on November 2, 2026, 1:21 PM EST. This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
Tornado records: NOAA/NWS Storm Prediction Center, Severe Weather Database, tornadoes 1950–2025 (https://www.spc.noaa.gov/wcm/data/1950-2025_actual_tornadoes.csv, downloaded 2 November 2026). Public domain; not endorsed by NOAA. Compiled by Global Incident Tracker.
Questions about Maricopa County
What natural disasters is Maricopa County, Arizona most at risk from?
Maricopa County, Arizona has a Very High natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 99.9 out of 100, higher than about 99% of US counties, with heat waves, inland (river and flash) flooding and wildfires scoring highest of its 18 hazards and $2.2 billion a year in expected losses.
How many federal disaster declarations has Maricopa County had?
OpenFEMA lists 24 federal disaster declarations that included Maricopa County since 1966, not counting 2 for COVID-19; the latest is FM-5501-AZ (Boulder View Fire, declared 28 June 2024). Another 27 Arizona declarations were made statewide without a county list.
How many tornadoes have hit Maricopa County?
NOAA's Storm Prediction Center recorded 75 tornadoes touching Maricopa County from 1950 to 2025. The deadliest: 30 Aug 1971, F2, 4.7 mi path, 0 killed, 41 injured (deaths and injuries are for the whole path).
Is the National Risk Index a flood zone map?
No. The National Risk Index is a planning-level estimate for a whole county, built for nationwide comparison. It does not tell you the flood zone or the risk of a single property: for that, look up the address on FEMA's Flood Map Service Center (msc.fema.gov) and ask your local floodplain manager.