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Natural hazard risk in Delaware County, Pennsylvania

Updated October 30, 2026. Based on FEMA, NOAA and OpenFEMA data. Published by Humblebee.

FEMA overall Risk Index rating: Relatively Moderate (score 92.9 of 100)[5]

Expected annual loss (FEMA)
$134.9 million[1]
Federal disaster declarations since 1965
22[2]
NFIP flood claims paid, 1978 to 2026
$57.2 million[3]
Tornadoes recorded, 1950 to 2024
6[4]

FEMA's National Risk Index (version 1.20, December 2025) rates overall natural hazard risk in Delaware County, Pennsylvania, Relatively Moderate compared with other US counties[5]. Within the county, the hazards with the highest FEMA scores are winter weather, strong wind and heat wave[6].

FEMA risk ratings for each hazard

Ratings and expected losses from the FEMA National Risk Index. Each rating compares this county with all US counties for that hazard, from Very Low to Very High. They are planning estimates, not predictions, and they do not describe any single property.

FEMA's National Risk Index estimates Expected Annual Loss from all 18 natural hazards in Delaware County at $134.9 million a year, with buildings accounting for $96.0 million[1]. This is FEMA's estimate of average yearly economic loss, not money anyone paid, and it is not meant to predict next year's damage[7]. FEMA estimates inland flooding Expected Annual Loss at $73.9 million a year[8], earthquake at $13.3 million[9] and heat wave at $12.8 million[10]. FEMA rates Social Vulnerability Relatively Low (score 32.9), a measure of how susceptible social groups are to the harm hazards cause[11]. FEMA rates Community Resilience Very High (score 84.2), a measure of the ability to prepare for, withstand and recover from hazards[12].

Hazards sorted by FEMA hazard-type Risk Index score, highest first
HazardFEMA risk ratingExpected annual loss
Winter WeatherVery High$2.1 million[13]
Strong WindRelatively High$5.2 million[14]
Heat WaveRelatively High$12.8 million[10]
LightningRelatively High$2.1 million[15]
EarthquakeRelatively Moderate$13.3 million[9]
Inland FloodingRelatively High$73.9 million[8]
TornadoRelatively High$9.4 million[16]
Cold WaveRelatively High$8.5 million[17]
HurricaneRelatively Moderate$5.9 million[18]
Ice StormRelatively High$750,000[19]
Coastal FloodingRelatively Moderate$730,000[20]
LandslideVery Low$2,758[21]
DroughtRelatively Low$209,000[22]
WildfireVery Low$13,000[23]
HailVery Low$46,000[24]
AvalancheVery Low$11[25]

Rated Not Applicable by FEMA for this county: volcanic activity[26].

Social vulnerability and community resilience

FEMA uses these two ratings to scale expected losses into the Risk Index.

FEMA measureRatingScore
Social vulnerabilityRelatively Low32.9[11]
Community resilienceVery High84.2[12]

Flooding and flood insurance

FEMA rates inland flooding risk in Delaware County Relatively High (score 94.4)[8] and coastal flooding risk Relatively Moderate (score 63.6) compared with other US counties[20]. OpenFEMA data as of 2026-08-03 show 1,153 residential flood insurance contracts in force out of 170,879 residential structures, a penetration rate of 0.7%[27]. A HazardFacts tally of OpenFEMA NFIP claims for losses from 1978 to 2026 counts 3,034 claims, 2,405 of them with a payment, and NFIP paid $57.2 million in total[3]. The years with the most paid claims were 1999 (424), 2004 (293) and 2010 (271)[3].

Measure Value
Inland Flooding, FEMA risk rating[8] Relatively High, $73.9 million expected loss a year
Coastal Flooding, FEMA risk rating[20] Relatively Moderate, $730,000 expected loss a year
NFIP residential flood policies in force (2026)[27] 1,153 of 170,879 homes
Homes in FEMA's mapped high-risk flood area (SFHA)[27] 1,813, of which 700 insured
NFIP flood claims, 1978 to 2026[3] 3,034 filed, $57.2 million paid

Is a specific address in a flood zone? Only FEMA's flood maps answer that, property by property[28]. This page describes the whole county.

Search an address on the FEMA Flood Map Service Center

Disaster declarations and tornado records

OpenFEMA lists 22 federal disaster declarations for natural hazards that include Delaware County since 1965, including 15 major disaster declarations[2]. By incident type, 7 were for hurricanes, 6 for floods and 4 for severe storms[2]. The most recent was DR-4618-PA, Remnants Of Hurricane Ida, declared 2021-09-10[29]. NOAA's Storm Prediction Center tornado database records 6 tornadoes in the county from 1950 to 2024, the strongest rated EF2, most recently on 2019-10-31[4].

Federal disaster declarations for natural hazards that include Delaware County, since 1965
Incident type Declarations
Hurricane[2] 7
Flood[2] 6
Severe Storm[2] 4
Snowstorm[2] 3
Drought[2] 1
Severe Ice Storm[2] 1
Most recent declarations
Declaration Incident Declared
DR-4618-PA[29] Remnants Of Hurricane Ida 2021-09-10
EM-3367-PA[29] Severe Winter Storm 2014-02-06
EM-3356-PA[29] Hurricane Sandy 2012-10-29
DR-4030-PA[29] Tropical Storm Lee 2011-09-12
EM-3340-PA[29] Remnants Of Tropical Storm Lee 2011-09-08

How to prepare

Steps from Ready.gov, FEMA's preparedness site, for the hazards with the highest FEMA ratings here. Follow instructions from local officials and the National Weather Service when a warning is issued.

Winter storms and cold

Before

  • Insulate your home and learn how to keep pipes from freezing.
  • Install and test smoke and carbon monoxide detectors with battery backup.
  • Keep several days of supplies in case the power goes out, including medication and pet needs.
  • Put an emergency kit in your car with jumper cables, sand, blankets, water and snacks, and keep the tank full.

During

  • Under a winter storm warning, find shelter right away.
  • Stay off the roads if you can. If you are stuck in your car, stay inside it.
  • Run generators and grills only outdoors, away from windows, and never heat your home with an oven or stove.

Source: Ready.gov, winter storms and cold

Extreme heat

Before

  • Learn the signs of heat illness and how to respond.
  • Do not rely on a fan as your main way to stay cool. Fans do not lower body temperature.
  • Find cool public places, such as libraries or malls, or ask your local health department.
  • Keep heat out with window shades, weather stripping and insulation.
  • If you cannot afford cooling costs, contact LIHEAP for help.

During

  • Never leave a person or an animal in a parked car in warm weather.
  • If your home has no air conditioning, go to a cooling center.
  • Wear light, loose clothing, drink plenty of fluids and avoid hard outdoor work in the middle of the day.

Source: Ready.gov, extreme heat

Earthquakes

Before

  • Practice Drop, Cover, and Hold On with your family and coworkers.
  • Sign up for earthquake alerts that can warn you before shaking starts.
  • Make a plan with an out-of-state contact and a place to meet if you get separated.
  • Anchor heavy items such as bookcases, refrigerators and water heaters, and keep heavy things on low shelves.
  • Consider earthquake insurance. Standard homeowners policies do not cover earthquake damage.

During

  • Drop to your hands and knees, cover your head and neck, and hold on until the shaking stops.
  • Indoors, stay where you are and avoid doorways. Outdoors, move to an open area away from buildings and power lines.
  • If you are driving, pull over, stop and set the parking brake.

Source: Ready.gov, earthquakes

Questions people ask

Is Delaware County, PA at risk of flooding?
FEMA rates inland flooding risk in Delaware County Relatively High compared with other US counties, with an estimated Expected Annual Loss of $73.9 million a year[8]. NFIP paid $57.2 million for flood claims for losses from 1978 to 2026[3].
How do I check if an address in Delaware County is in a flood zone?
Look up the address on FEMA's Flood Map Service Center, the official source for flood maps, or ask the local floodplain manager[28]. County ratings do not tell you the flood zone of a single address[28].
Does Delaware County, PA get tornadoes?
NOAA's Storm Prediction Center tornado database records 6 tornadoes in Delaware County from 1950 to 2024, the strongest rated EF2[4]. FEMA rates tornado risk Relatively High compared with other US counties (score 92.4)[16].
Is Delaware County at risk of hurricanes or earthquakes?
FEMA rates hurricane risk Relatively Moderate (score 88.1)[18] and earthquake risk Relatively Moderate (score 94.4) compared with other US counties[9]. OpenFEMA lists 7 hurricane disaster declarations that include the county since 1965[2].
How many federal disasters have been declared in Delaware County, PA?
OpenFEMA lists 22 federal disaster declarations for natural hazards that include Delaware County since 1965[2]. The most recent was for the Remnants Of Hurricane Ida, declared 2021-09-10[29].

Facts and sources

  1. FEMA National Risk Index (version 1.20, December 2025): Expected Annual Loss from all 18 natural hazards in Delaware County is $134.9 million a year (Expected Annual Loss rating Relatively Moderate, score 93.3). Of this, buildings account for $96.0 million, injuries and deaths (converted to dollars by FEMA) for... FEMA National Risk Index
  2. OpenFEMA Disaster Declarations Summaries list 22 federal disaster declarations for natural hazards that include Delaware County since 1965 (15 major disaster, 7 emergency or fire management). By incident type: hurricane 7, flood 6, severe storm 4, snowstorm 3, drought 1, severe ice storm 1. Biological (such as... OpenFEMA Disaster Declarations
  3. HazardFacts tally of OpenFEMA NFIP Redacted Claims (losses from 1978 to 2026): 3,034 National Flood Insurance Program claims were filed for losses in Delaware County, 2,405 of them with a payment, and NFIP paid $57.2 million in total (building, contents and increased cost of compliance, in dollars of the year... OpenFEMA NFIP claims
  4. NOAA Storm Prediction Center tornado database (1950 to 2024): 6 recorded tornadoes touched Delaware County. The strongest were rated EF2 (most recent of them on 2019-10-31). 0 were rated F3/EF3 or stronger. The most recent recorded tornado was on 2019-10-31. Ratings used the Fujita scale until early 2007 and the... NOAA Storm Prediction Center
  5. FEMA National Risk Index (version 1.20, December 2025): the overall natural hazard Risk Index rating for Delaware County is Relatively Moderate, with a Risk Index score of 92.9 out of 100. The score is the county's percentile rank among all US counties. FEMA National Risk Index
  6. Among the 18 hazards in the FEMA National Risk Index (version 1.20, December 2025), the hazards with the highest hazard-type Risk Index scores for Delaware County are winter weather (99.2, Very High), strong wind (97.7, Relatively High), heat wave (97.5, Relatively High). HazardFacts sorted FEMA's published scores;... FEMA National Risk Index
  7. FEMA's National Risk Index FAQ (December 2025): Expected Annual Loss is FEMA's estimate of the average economic loss in dollars from natural hazards each year. The index is not meant to predict how much damage a community will have in the next year, and a hazard can still cause damage where a rating is low. Scores... FEMA National Risk Index documentation
  8. FEMA National Risk Index (version 1.20, December 2025), inland flooding in Delaware County: Risk Index rating Relatively High (score 94.4 of 100). Expected Annual Loss $73.9 million a year (rating Relatively High). Annualized frequency 4.64 event-days per year, from recorded occurrences over a period of record of... FEMA National Risk Index
  9. FEMA National Risk Index (version 1.20, December 2025), earthquake in Delaware County: Risk Index rating Relatively Moderate (score 94.4 of 100). Expected Annual Loss $13.3 million a year (rating Relatively Moderate). FEMA's modeled annual frequency is 0.0016 events per year. FEMA National Risk Index
  10. FEMA National Risk Index (version 1.20, December 2025), heat wave in Delaware County: Risk Index rating Relatively High (score 97.5 of 100). Expected Annual Loss $12.8 million a year (rating Relatively High). Annualized frequency 11.06 event-days per year, from recorded occurrences over a period of record of 18 years. FEMA National Risk Index
  11. FEMA National Risk Index (version 1.20, December 2025): Social Vulnerability rating for Delaware County is Relatively Low (score 32.9). FEMA describes social vulnerability as how susceptible social groups are to the harm natural hazards cause. FEMA National Risk Index
  12. FEMA National Risk Index (version 1.20, December 2025): Community Resilience rating for Delaware County is Very High (score 84.2). FEMA describes community resilience as a community's ability to prepare for, withstand and recover from hazards. FEMA National Risk Index
  13. FEMA National Risk Index (version 1.20, December 2025), winter weather in Delaware County: Risk Index rating Very High (score 99.2 of 100). Expected Annual Loss $2.1 million a year (rating Very High). Annualized frequency 10.49 events per year, from recorded occurrences over a period of record of 18 years. FEMA National Risk Index
  14. FEMA National Risk Index (version 1.20, December 2025), strong wind in Delaware County: Risk Index rating Relatively High (score 97.7 of 100). Expected Annual Loss $5.2 million a year (rating Relatively High). Annualized frequency 6.94 events per year, from recorded occurrences over a period of record of 38 years. FEMA National Risk Index
  15. FEMA National Risk Index (version 1.20, December 2025), lightning in Delaware County: Risk Index rating Relatively High (score 95.6 of 100). Expected Annual Loss $2.1 million a year (rating Relatively High). Annualized frequency 35.98 events per year, from recorded occurrences over a period of record of 24 years. FEMA National Risk Index
  16. FEMA National Risk Index (version 1.20, December 2025), tornado in Delaware County: Risk Index rating Relatively High (score 92.4 of 100). Expected Annual Loss $9.4 million a year (rating Relatively High). Annualized frequency 0.1 events per year, from recorded occurrences over a period of record of 38 years. FEMA National Risk Index
  17. FEMA National Risk Index (version 1.20, December 2025), cold wave in Delaware County: Risk Index rating Relatively High (score 91.5 of 100). Expected Annual Loss $8.5 million a year (rating Relatively High). Annualized frequency 0.79 event-days per year, from recorded occurrences over a period of record of 18 years. FEMA National Risk Index
  18. FEMA National Risk Index (version 1.20, December 2025), hurricane in Delaware County: Risk Index rating Relatively Moderate (score 88.1 of 100). Expected Annual Loss $5.9 million a year (rating Relatively Moderate). Annualized frequency 0.09 events per year, from recorded occurrences over a period of record of 172... FEMA National Risk Index
  19. FEMA National Risk Index (version 1.20, December 2025), ice storm in Delaware County: Risk Index rating Relatively High (score 87.0 of 100). Expected Annual Loss $750,000 a year (rating Relatively High). Annualized frequency 1.41 event-days per year, from recorded occurrences over a period of record of 68 years. FEMA National Risk Index
  20. FEMA National Risk Index (version 1.20, December 2025), coastal flooding in Delaware County: Risk Index rating Relatively Moderate (score 63.6 of 100). Expected Annual Loss $730,000 a year (rating Relatively Moderate). FEMA's modeled annual frequency is 3.687 events per year. FEMA National Risk Index
  21. FEMA National Risk Index (version 1.20, December 2025), landslide in Delaware County: Risk Index rating Very Low (score 59.4 of 100). Expected Annual Loss $2,758 a year (rating Very Low). FEMA National Risk Index
  22. FEMA National Risk Index (version 1.20, December 2025), drought in Delaware County: Risk Index rating Relatively Low (score 54.1 of 100). Expected Annual Loss $209,000 a year (rating Relatively Low). Annualized frequency 5.71 event-days per year, from recorded occurrences over a period of record of 22 years. FEMA National Risk Index
  23. FEMA National Risk Index (version 1.20, December 2025), wildfire in Delaware County: Risk Index rating Very Low (score 27.6 of 100). Expected Annual Loss $13,000 a year (rating Very Low). FEMA's modeled annual frequency is 0.0001 events per year. FEMA National Risk Index
  24. FEMA National Risk Index (version 1.20, December 2025), hail in Delaware County: Risk Index rating Very Low (score 13.2 of 100). Expected Annual Loss $46,000 a year (rating Very Low). Annualized frequency 2.47 events per year, from recorded occurrences over a period of record of 37 years. FEMA National Risk Index
  25. FEMA National Risk Index (version 1.20, December 2025), avalanche in Delaware County: Risk Index rating Very Low (score 11.4 of 100). Expected Annual Loss $11 a year (rating Very Low). Annualized frequency 0.01 events per year, from recorded occurrences over a period of record of 28 years. FEMA National Risk Index
  26. FEMA National Risk Index (version 1.20, December 2025) rates these hazards Not Applicable for Delaware County: volcanic activity. FEMA uses Not Applicable when its source data has no historical record of the hazard in the community and the hazard is not considered geographically possible there. FEMA National Risk Index documentation
  27. NFIP Residential Penetration Rates (OpenFEMA, as of 2026-08-03): 1,153 residential flood insurance contracts were in force in Delaware County, out of 170,879 residential structures, a penetration rate of 0.7%. Inside FEMA's mapped Special Flood Hazard Area there were 1,813 residential structures and 700 contracts,... OpenFEMA NFIP penetration rates
  28. FEMA's Flood Map Service Center is the official public source for flood maps (Flood Insurance Rate Maps) produced under the National Flood Insurance Program. Flood zones apply to specific properties: look up an address there or ask the local floodplain manager. County-level ratings do not tell you the flood zone of... FEMA Flood Map Service Center
  29. Most recent federal disaster declarations for natural hazards (table on this page). OpenFEMA Disaster Declarations

FEMA's National Risk Index compares each county with all other US counties. Ratings are relative (Very Low to Very High), not a measure of safety. Never call a place safe, unsafe, good or bad to live in. Risk Index and Expected Annual Loss values are FEMA estimates for planning. They do not predict next year's losses and do not apply to a single property. Flood zones are set by FEMA flood maps for specific properties. County ratings and flood insurance counts do not tell anyone whether an address is in a flood zone. Disaster declaration, NFIP and tornado counts are records of the past for this county only. Do not compare with other counties unless a fact does.

Federal Emergency Management Agency (FEMA), National Risk Index Dataset: National Risk Index Counties, v1.20 (December 2025). Retrieved from fema.maps.arcgis.com on October 30, 2026. 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). This product uses the FEMA OpenFEMA API, but is not endorsed by FEMA.