613 flood insurance claims·$10.7M paid·5 federal flood & hurricane disasters
Share of the whole county outline, rivers and lakes included; parts FEMA hasn’t mapped count as zero.
Shaded areas are FEMA’s mapped flood hazard zones in and around St. Mary's County, Maryland. Zoomed out they are simplified; at street level the map switches to FEMA’s exact layer. Tap anywhere to check that spot, or search an address above.
St. Mary's County experiences a mix of standard riverine floods, flash floods, and frequent tidal events, led by 86 general flood events, 82 coastal flood events, and 72 flash flood events over the last 30 years alongside 5 tropical storms and 3 storm surge events. Recent coastal flooding has been driven by strong southerly winds and pressure gradients, such as the event on January 9, 2024, that raised water levels to major levels along the western shore of the Chesapeake Bay, as well as moderate onshore flow combined with high astronomical tides during a New Moon on March 9, 2024, that caused moderate coastal flooding.
NFIP claim data indicates significant risk outside of primary high-risk zones. Zone A accounts for 337 claims with an average payout of $25,088 and an average recorded water depth of 5 inches. Meanwhile, Zone X properties have recorded 144 claims with an average payout of $23,847 and an average recorded water depth of 19 inches, Shaded Zone X has 55 claims with an average payout of $22,660 and an average water depth of 4 inches, and Unshaded Zone X has 43 claims with an average payout of $27,218 and an average water depth of 2 inches.
Homeowners, real estate agents, and journalists tracking property risk in St. Mary's County should pay the closest attention to coastal properties and structures located in both designated high-risk zones and moderate-to-low risk Zone X areas, where recorded flood depths can reach higher averages despite lower claim frequencies.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
22% of St. Mary's County’s flood insurance claims were on properties rated outside FEMA’s high-risk zones.
444 NFIP claims with a recorded rated flood zone, 1978 to date. The zone is the one FEMA used to rate that policy, which may not match today’s map. Source: OpenFEMA NFIP claims.
In flood insurance claims here that reported a flood depth, the average was 7 inches.
Drawn to scale against an 80-inch door. Even a few inches soaks flooring, the bottom of the drywall and anything plugged in near the floor.
Average of the depths reported on claims (zero and implausible values left out); FEMA’s record doesn’t say exactly where each depth was measured. Source: OpenFEMA NFIP claims.
The worst year was 2003, with 265 claims and $6.3M paid, the year of Hurricane Isabel.
Bar height is scaled by square root so ordinary years stay visible next to the worst one. NFIP claims by year of loss. Source: OpenFEMA.
51 NOAA storm reports from St. Mary's County describe what happened, in the words of the forecasters who covered it. Read the Maryland flood stories →
18 federal disaster declarations since 1977, 5 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Severe Winter Storm | Jan 23, 2026 |
| Tropical Storm Isaias | Aug 3, 2020 |
| Hurricane Sandy | Oct 26, 2012 |
| Severe Storms And Straight-line Winds | Jun 29, 2012 |
| Hurricane Irene | Aug 26, 2011 |
| Severe Winter Storms And Snowstorms | Feb 5, 2010 |
| Hurricane Katrina Evacuation | Aug 29, 2005 |
| Hurricane Isabel | Sep 18, 2003 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
248 since 1996: 72 flash floods, 86 river or area floods and 85 coastal floods or surges.
| Event | Date | Damage |
|---|---|---|
| Coastal Flood | Apr 19, 2024 | — |
| Coastal Flood | Apr 12, 2024 | — |
| Coastal Flood | May 11, 2024 | — |
| Coastal Flood | Mar 9, 2024 | — |
| Coastal Flood | Jan 9, 2024 | — |
| Coastal Flood | Feb 6, 2024 | — |
| Coastal Flood | Apr 3, 2024 | — |
| Coastal Flood | Apr 30, 2023 | — |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
Coastal Flood · Apr 19, 2024. Easterly onshore flow followed by southerly winds resulted in moderate coastal flooding at Annapolis and St. Mary's County.
Coastal Flood · Apr 12, 2024. Strong southerly flow ahead of a low pressure system resulted in moderate coastal flooding at Annapolis and Straits Point.
Coastal Flood · May 11, 2024. Elevated water levels due to onshore flow resulted in moderate coastal flooding at Straits Point MD and Annapolis for multiple high tide cycles.
Coastal Flood · Mar 9, 2024. A moderate onshore flow combined with high astronomical tides due to a New Moon resulted in moderate coastal flood event at Annapolis and St. Mary's Counties.
National Weather Service narratives, lightly trimmed. Source: NOAA Storm Events Database.
Every colour on the map above is a place on this drawing: where the ground sits relative to the flood FEMA plans for.
If a building in St. Mary's County is in a high-risk zone (A or V) and its mortgage comes from a federally regulated or insured lender, or is federally backed, flood insurance is required.
Outside those zones it is optional, and often worth having: from 2014 to 2024 nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area. Since Risk Rating 2.0, NFIP premiums are set for each building, so the only reliable price is a quote: FloodSmart.gov or a local agent.