Frederick County

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Frederick County: 0.
2. Weak tornadoes were under-recorded before Doppler radar coverage became national in the early 1990s, so earlier decades read low. Ratings use the Fujita scale before February 2007 and the Enhanced Fujita scale after.

Storm Prediction Center severe weather database, 1950 to 2025.

Every storm within 100 miles

1. Tropical storms and hurricanes (34 kt or more, still tropical) at closest approach. Post-tropical remnants with gale-force winds are listed but not counted. Direct: track within 50 miles; near: within 100 miles. Distance is measured to the county boundary for counties and to the city centre for cities, using positions interpolated hourly between HURDAT2 fixes.

National Hurricane Center HURDAT2, 1851 to 2025.

Smoke overhead

1. A smoke day is a date on which a smoke plume traced by NOAA Hazard Mapping System analysts from satellite imagery covered this place's point (the county's population centre or the city centre). Counts here are of medium or heavy smoke. Since 2018 analysts have often drawn light smoke as one area over most of the continent, so light-smoke counts are not comparable from year to year. The plumes show smoke anywhere in the air above, not air quality at the ground, and smoke hidden by cloud is missed.

NOAA Hazard Mapping System smoke analysis, 2011 to 2026, retrieved October 30, 2026.

Claims by ZIP code

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).

OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026. NOAA Storm Events through 2026.

River crests

River gauges

1. Crests are the highest and the recent crests the National Weather Service lists for each river gauge in the county that has a flood stage, not every flood. Flood categories use each gauge's current flood stages; crests from before levees, dams or channel changes may not be comparable. Crests measured on an old datum are left out of the rankings.

NOAA National Water Prediction Service gauge records, retrieved October 30, 2026.

1. The Palmer Drought Severity Index is computed by NOAA each month from the county's average temperature and precipitation, relative to the county's own climate. Zero is normal; -3 or lower is severe drought and -4 or lower extreme drought. It describes the long-term balance of moisture, not water supply or crop losses.

NOAA NCEI nClimDiv county Palmer Drought Severity Index, 1895 to September 2026, issued October 6, 2026.

Every earthquake of magnitude 4 or more within 50 miles

1. Earthquakes of magnitude 2.5 or more in the USGS Comprehensive Catalog since 1900. Within 50 miles means the epicentre lies within 50 miles of the county boundary (or inside the county).
2. Small earthquakes were under-recorded before the modern seismic networks of the 1970s and are still missed in remote areas, so early decades read low. Magnitudes are as the catalogue reports them and mix scales (moment, local and body-wave).

USGS ANSS Comprehensive Earthquake Catalog, 1900 to present, retrieved October 30, 2026.

Mapped landslides

Mapped by NASA (2).

1. Landslides mapped in the USGS compilation of landslide inventories across the United States (version 3.0, 2025), rated probable or better. The compilation joins inventories made by federal and state agencies for different purposes and areas, so the number mapped in a county reflects how closely it has been surveyed as much as how often its slopes fail. An area with few records may simply not have been mapped. Deaths are as recorded in the inventories; a slide listed in two inventories is counted once.

USGS Landslide Inventories across the United States, version 3.0, retrieved October 27, 2026.

More event types since 1996

Costliest events since 1996

1. May 15, 2018Flash Flood$43.2 million
   National Weather Service narrative

   Significant flash flooding occurred during the evening of May 15th from the city of Frederick southwestward toward Braddock Heights and Jefferson. The amount of damage shown here is total damage not already accounted for in other reports.

2. Jan 19, 1996Flood, Frederick$15.0 million
   National Weather Service narrative

   *** River Flooding ***High dew point temperatures melted most of the snow on the ground within 12 hours, with liquid water equivalent ranging from 1 to 3 inches. Snowmelt combined with 1 to 3 inches of rain (some locations received 5 inches) to produce, in some cases, catastrophic river flooding. The flooding was the worst in the region since 1985. River flooding began during the flood/flash flood event along the headwaters of the basins and continued downstream through the 22nd. Crests ranged from 3 to 21 feet above flood stage. Record flooding occurred on Wills Creek near Cumberland (MDZ002), damaging all dwellings in the town of Locust Grove. Almost all dwellings in the town of…

3. Jun 19, 1996Flash Flood$5.0 million
4. Oct 29, 2012High Wind, Frederick$1.2 million
   National Weather Service narrative

   Wind gusts of 58-61 mph were measured at Frederick Airport. A public library in Thurmont may have sustained structural damage due to a fallen tree. Numerous power outages occurred and most of them were north of Frederick along Highway 17.

5. Jun 14, 2026Thunderstorm Wind$1.0 million
   National Weather Service narrative

   On June 15, 2026, a survey team from the National Weather Service|Baltimore/Washington Weather Forecast Office conducted a formal|storm assessment in Frederick County, Maryland. The objective of|the field survey was to analyze the thunderstorm wind damage that|occurred during the evening of Sunday, June 14, 2026. The event|began at approximately 7:30 PM EDT, when a cluster of showers|initiated in central Jefferson County, West Virginia. This|convective system tracked continuously northeastward into|Frederick County, Maryland, while exhibiting steady|intensification.||As the storm progressed east of Libertytown, Maryland, it|generated a localized zone of significant structural and…

6. May 15, 2018Flash Flood$1.0 million
   National Weather Service narrative

   Floodwaters were more than two feet deep on North Market Street near the Frederick YMCA. Water entered buildings in the area and several parked cars were mostly submerged in water. The YMCA building itself had water enter the building with an estimated 40,000 sqft of the 95,000 sqft facility suffering water damage.

7. Aug 14, 1999Tornado$800,000
   National Weather Service narrative

   Moderate damage to buildings, trees downed onto homes and cars

8. Aug 7, 2000Lightning$750,000
   National Weather Service narrative

   Lightning started a fire in the attic of an apartment complex.

9. Sep 6, 1996Flood, Frederick$500,000
   National Weather Service narrative

   Torrential rains associated with Tropical Storm Fran caused the rapid onset of river flooding along the headwaters of the Potomac River late on the 6th, spreading gradually southeast throughout the entire basin by early on the 10th. Crests were similar to those seen in January 1996 across the Lower main stem of the Potomac. Levels were 1 to 5 feet higher than in January across the Upper main stem of the Potomac.Western Allegany Co (MDZ002) was hit the hardest. The nearly $1 million in property damage included 14 destroyed homes, 19 with major damage, and 500 with minor to moderate damage. The damage was concentrated along the Potomac and the Georges Creek in the towns of…

10. Apr 19, 2025Thunderstorm Wind$500,000
    National Weather Service narrative

    A wind gust of 70 knots (81 MPH) was measured by the AWOS at Camp David (KRSP). Hundreds of trees, limbs, wires, and poles blew down around Thurmont and Emmitsburg. Trees blew down on MD-77 Foxville Road at Herman Hauver Road, and on MD-550 Jimtown Road east of US-15. Numerous tree limbs blew down southeast of Thurmont toward New Midway. Five large 60-foot tall pine trees blew down near Thurmont, one of which crushed an unoccupied vehicle; there were also ten trees snapped at the top near this location.

1. Storm Events records before 1996 cover only tornadoes, thunderstorm wind and hail. Damage figures are as reported by the National Weather Service at the time, not adjusted for inflation.

NOAA NCEI Storm Events Database, 1950 to 2026, issued October 26, 2026.

All-time high

103°F2 times, most recently Aug 20, 1983

All-time low

−27°FJan 21, 1994

Warmest night

81°FJul 25, 2010

Coldest day

7°FJan 20, 1994

Wettest day

7.50 inSep 14, 1966

Snowiest day

24.0 inFeb 6, 2010

Hottest year

1998mean 56.2°F

Coldest year

1978mean 50.8°F

Wettest year

201877.16 in

Driest year

200130.19 in

Snowiest season

84.0 in1995-96

Station Emmitsburg 2 Se (USC00182906), 403 ft elevation, 18.2 miles from the population centre. Daily records from 1956 to October 26, 2026; 91.0% of days in the last 30 years are complete. Records at a single station can differ from a city’s official threaded record, which may combine several stations.

NOAA NCEI Global Historical Climatology Network Daily.

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).

OpenFEMA Disaster Declarations Summaries, retrieved October 30, 2026. Statewide declarations are not listed.

Neighbouring counties

• Tornadoes NOAA Storm Prediction Center severe weather database, through 2025.
• Tropical cyclones NOAA National Hurricane Center HURDAT2 (Atlantic; Northeast and Central Pacific), through 2025.
• Wildfire USGS/USFS Monitoring Trends in Burn Severity, through 2026.
• Storm events NOAA NCEI Storm Events Database, through 2026.
• Flood insurance OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026.
• Declarations OpenFEMA Disaster Declarations Summaries v2, retrieved October 30, 2026.
• Weather records NOAA NCEI Global Historical Climatology Network Daily, station USC00182906.
• River crests NOAA National Weather Service, National Water Prediction Service river gauges, retrieved October 30, 2026.
• Drought NOAA NCEI nClimDiv county Palmer Drought Severity Index, through September 2026.
• Smoke NOAA NESDIS Hazard Mapping System smoke analysis, retrieved October 30, 2026.
• Landslides USGS Landslide Inventories across the United States, version 3.0 (2025).
• Earthquakes USGS ANSS Comprehensive Earthquake Catalog (ComCat), retrieved October 30, 2026.

Joins, thresholds and known limits are set out in the methodology. Found an error? Report it. Page built October 30, 2026.