Chester County, Pennsylvania: hazard history

FEMA declared 26 disasters that named Chester County between 1965 and 2021.

Most recent declarations

• DR-4618 2021 · Hurricane · Remnants Of Hurricane Ida
• EM-3441 2020 · Biological · Covid-19
• DR-4506 2020 · Biological · Covid-19 Pandemic
• DR-4267 2016 · Snowstorm · Severe Winter Storm And Snowstorm
• EM-3367 2014 · Severe Ice Storm · Severe Winter Storm
• EM-3356 2012 · Hurricane · Hurricane Sandy
• DR-4030 2011 · Flood · Tropical Storm Lee
• EM-3340 2011 · Flood · Remnants Of Tropical Storm Lee
• EM-3339 2011 · Hurricane · Hurricane Irene
• DR-4025 2011 · Hurricane · Hurricane Irene

Not counted above: 6 statewide declarations, which covered every county in Pennsylvania. A declaration is a decision to send federal help, not a measure of how bad an event was. Records run from 1953. Source: FEMA OpenFEMA Disaster Declarations Summaries.

Records start in 1996. Damage is NOAA's estimate at the time, in nominal dollars, and is often rounded; it is not insurance claims data. A storm that crossed two NOAA zones in this county is recorded, and counted, once per zone.

NOAA storm event records in Chester County each year. The busiest year was 2020, with 176 records.

Years with no record are left out of the table, not shown as zero.

Costliest records

1. Flash Flood · Sep 1, 2021$40.0M
   NOAA name: CHESTER · 1 death · NOAA record 981414
2. High Wind · Sep 18, 2003$6.7M
   NOAA name: CHESTER · NOAA record 5336708
3. Flood · Jun 27, 2006$6.0M
   NOAA name: CHESTER · NOAA record 5518456
4. Winter Storm · Feb 9, 2010$5.0M
   NOAA name: CHESTER · NOAA record 212812
5. Flash Flood · Sep 15, 2003$3.5M
   NOAA name: CHESTER · NOAA record 5371968

Deadliest records

1. Heat · Jul 4, 19994 deaths
   NOAA name: CHESTER · NOAA record 5715465
2. Heat · Aug 1, 20023 deaths
   NOAA name: CHESTER · NOAA record 5318172
3. Heat · May 6, 20002 deaths
   NOAA name: CHESTER · NOAA record 5144692
4. Thunderstorm Wind · Jul 18, 20062 deaths
   NOAA name: CHESTER · 1 injury · NOAA record 5522793
5. Heavy Rain · May 25, 19971 death
   NOAA name: CHESTER · NOAA record 5609078

Each line is one NOAA record, linked to its page at NOAA. One large storm can appear more than once if NOAA recorded it in several zones of this county. Dollars are nominal.

The National Flood Insurance Program paid $37.4M on 1,893 claims in Chester County from 1978 to 2024.

A count of claims, not a rate: NFIP publishes no count of insured homes beside it, and most flood damage is uninsured. Nominal dollars. Records run from 1978 to 2024; claims filed without a county code are not on any county page. Source: FEMA OpenFEMA FIMA NFIP Redacted Claims.

A hazard vulnerability analysis rates each hazard for probability, impact, preparedness and response. Probability is the one column the county’s federal record can fill — NCEI storm events from 1996 to 2026 and FEMA declarations naming the county — and this is what it says for a facility here, on the 0–3 scale of the all-hazards structure surveyors expect. The other six columns are the facility’s own judgment about its building, and Calchis leaves them blank.

A dash means the record does not speak to that hazard; it is not a zero. Whether a finished document satisfies the CMS Emergency Preparedness Rule is the facility’s finding and its surveyor’s. Complete the HVA for a facility in Chester County — the technological, human and hazardous-materials rows, the six facility columns, the approval and the printed document — or read the sample analysis on that page first.

• Every figure is counted from public federal records held by Calchis: NOAA NCEI Storm Events, FEMA OpenFEMA Disaster Declarations, and FEMA NFIP claims. Nothing is modeled or estimated.
• NOAA files some events by county and others by forecast zone, and names both. Records are counted as Chester County when their NOAA name is this county's name, alone or with a word like “Coastal” or “Inland” in front. The county codes NOAA also publishes have not been loaded for Pennsylvania yet; when they are, this page will count by code instead, and some counties' records will grow. NOAA names counted here: CHESTER, EASTERN CHESTER, Eastern Chester, WESTERN CHESTER, Western Chester. Zones named for something else, such as a mountain range or two counties at once, are left out: 0% of Pennsylvania's NOAA records.
• Counts last rebuilt from the source records on Sep 15, 2026.