Enter any address in Montgomery County, Maryland to see its FEMA flood zone
Flash flooding from slow-moving thunderstorms is the dominant flood character in Montgomery County. Over the last 30 years, NOAA Storm Events data shows 242 flash flood events and 186 flood events. For example, in May 2025, heavy rainfall from a slow-moving weather system led to widespread flash flooding, with localized totals of four to eight inches in some areas. Later that summer, in July 2025, a combination of a cold front, unstable atmosphere, and tropical moisture produced slow-moving thunderstorms that resulted in scattered flash flooding across the county, with rainfall averaging two to four inches.
National Flood Insurance Program (NFIP) claims data indicates that properties in Zone X have experienced the most claims (379), with an average payout of $6,203 and an average water depth of 3.2 feet. However, Zone X_UNSHADED saw the highest average payout ($12,148) despite a lower average water depth (0.5 feet). Homeowners in Zone X_SHADED experienced the deepest average water depth at 4.3 feet, with 10 claims. Residents in areas designated as Zone A, X, X_UNSHADED, and X_SHADED should pay close attention to flood risk.
Summary generated from NOAA storm narratives and NFIP claim data for this county. Not predictive.
131 NOAA storm reports from this county describe what happened, in the words of the meteorologists who were there.
Montgomery County, Maryland has recorded 429 flood-related events since 1996 according to NOAA's Storm Events Database, including 242 flash floods and 186 river or area floods. The county has received 21 federal disaster declarations, 3 of which involved flooding or coastal storms. Enter any address above to check its FEMA flood zone designation.
FEMA Disaster Declarations (1971–2026)
Source: OpenFEMA Disaster Declarations Summaries.
| Declaration | Type | Date |
|---|---|---|
| Severe Winter Storm | Winter Storm | Jan 23, 2026 |
| Covid-19 | Biological | Jan 20, 2020 |
| Covid-19 Pandemic | Biological | Jan 20, 2020 |
| Severe Winter Storm And Snowstorm | Snowstorm | Jan 22, 2016 |
| Hurricane Sandy | Hurricane | Oct 26, 2012 |
| Severe Storms And Straight-line Winds | Severe Storm | Jun 29, 2012 |
| Hurricane Irene | Hurricane | Aug 26, 2011 |
| Severe Winter Storms And Snowstorms | Snowstorm | Feb 5, 2010 |
| Severe Winter Storm And Snowstorm | Snowstorm | Dec 18, 2009 |
| Severe Storms, Flooding, And Tornadoes | Severe Storm | Jun 22, 2006 |
NOAA Storm Events Database (1996–2025)
Source: NOAA National Weather Service Storm Events Database.
| Type | Date | Damage |
|---|---|---|
| Flash Flood | Jul 31, 2025 | 0.00K |
| Flash Flood | Jul 19, 2025 | 0.00K |
| Flash Flood | Jun 18, 2025 | 0.00K |
| Flood | May 15, 2025 | 0.00K |
| Flood | May 14, 2025 | 0.00K |
| Flash Flood | Jul 14, 2025 | 0.00K |
| Flash Flood | Jul 12, 2025 | 0.00K |
| Flood | Jul 1, 2025 | 0.00K |
| Flood | Jan 28, 2024 | 0.00K |
| Flash Flood | Aug 17, 2024 | 0.00K |
Flash Flood — Jul 31, 2025
A slow moving cold front combined with a highly unstable atmosphere along with tropical moisture to produce slow moving thunderstorms with heavy rainfall. Some of these storms trained over the same areas, resulting in scattered to numerous instances of flash flooding. Total rainfall amounts in areas with flash flooding averaged two to four inches, though some localized amounts up to six inches ...
Flash Flood — Jul 19, 2025
An unstable atmosphere along with plenty of moisture led to the development of showers and thunderstorms. The thunderstorms were slow moving, and trained over the same areas in spots resulting in flash flooding. Localized rainfall totals of 2 to 4 inches were observed, with upwards of 5 inches in the most persistent thunderstorms.
Flash Flood — Jun 18, 2025
Multiple rounds of slow-moving showers and thunderstorms developed along a weak frontal boundary. These storms produced locally heavy rainfall from Montgomery County to Anne Arundel County. Rainfall amounts of two to four inches were observed with several hours.
Flood — May 15, 2025
A slow moving closed upper level low originating from the Gulf of America brought anomalous moisture into the area. A long duration period of rain ensued, with rain rates exceeding two inches an hour during the afternoon of May 13th. The slow moving storms coupled with training led to localized rainfall totals of four to eight inches across western Maryland, with lesser amounts of two to four i...
Flood — May 14, 2025
A slow moving closed upper level low originating from the Gulf of America brought anomalous moisture into the area. A long duration period of rain ensued, with rain rates exceeding two inches an hour during the afternoon of May 13th. The slow moving storms coupled with training led to localized rainfall totals of four to eight inches across western Maryland, with lesser amounts of two to four i...
Source: NOAA National Weather Service Storm Events Database.
Source: OpenFEMA NFIP Individual Claims (2.25M records analyzed).
FEMA assigns flood zone designations to areas in Montgomery County, Maryland:
AE High Risk — 1% annual chance of flooding. Insurance required.
VE Very High Risk — Coastal flooding with wave action.
X (Shaded) Moderate Risk — 500-year floodplain.
X Low Risk — Outside major floodplains.
Properties in Montgomery County, Maryland that are in FEMA-designated Special Flood Hazard Areas (zones A and V) with federally backed mortgages are required to carry flood insurance.
Even outside high-risk zones, flood insurance is recommended. From 2014 to 2024, nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area.
Visit FloodSmart.gov to find an agent and get a quote.