Enter any address in Cass County, North Dakota to see its FEMA flood zone
Flash flooding from summer thunderstorms is the dominant flood character in Cass County, North Dakota, with 50 such events recorded in the last 30 years. For example, localized flash flooding occurred during the evening of August 5th, 2025, following a cluster of thunderstorms. Another significant event on June 20th, 2025, brought severe weather including a derecho that tracked across the region.
National Flood Insurance Program (NFIP) data shows a substantial number of claims filed in Cass County. Zone A, which has a high flood risk, has seen 1,433 claims with an average payout of $8,384 and an average water depth of 2.4 feet. Zone X_SHADED, representing moderate flood risk, has had 139 claims with an average payout of $10,617 and an average water depth of 3.7 feet. Properties in Zone A and Zone X_SHADED, as well as those without a Base Flood Elevation (BFE) determination, should pay the most attention to flood risk.
Summary generated from NOAA storm narratives and NFIP claim data for this county. Not predictive.
24 NOAA storm reports from this county describe what happened, in the words of the meteorologists who were there.
Cass County, North Dakota has recorded 87 flood-related events since 1996 according to NOAA's Storm Events Database, including 50 flash floods and 37 river or area floods. The county has received 35 federal disaster declarations, 23 of which involved flooding or coastal storms. Enter any address above to check its FEMA flood zone designation.
FEMA Disaster Declarations (1965–2025)
Source: OpenFEMA Disaster Declarations Summaries.
| Declaration | Type | Date |
|---|---|---|
| Severe Storm, Tornadoes, And Straight-line Winds | Severe Storm | Jun 20, 2025 |
| Severe Winter Storm And Straight-line Winds | Winter Storm | Dec 25, 2023 |
| Flooding | Flood | Apr 1, 2020 |
| Covid-19 | Biological | Jan 20, 2020 |
| Covid-19 Pandemic | Biological | Jan 20, 2020 |
| Flooding | Flood | Mar 21, 2019 |
| Flooding | Flood | Apr 22, 2013 |
| Flooding | Flood | Apr 5, 2011 |
| Flooding | Flood | Feb 14, 2011 |
| Flooding | Flood | Feb 26, 2010 |
NOAA Storm Events Database (1996–2025)
Source: NOAA National Weather Service Storm Events Database.
| Type | Date | Damage |
|---|---|---|
| Flash Flood | Jun 20, 2025 | 0.00K |
| Flash Flood | Aug 5, 2025 | 0.00K |
| Flood | May 21, 2024 | 0.50K |
| Flood | Dec 26, 2023 | 0.00K |
| Flood | Apr 20, 2023 | 951.00K |
| Flood | Apr 19, 2023 | 951.00K |
| Flood | Apr 17, 2023 | 951.00K |
| Flood | Apr 16, 2023 | 951.00K |
| Flash Flood | Aug 5, 2023 | 0.00K |
| Flood | May 1, 2023 | 0.00K |
Flash Flood — Jun 20, 2025
During the evening of Friday, June 20th into the early morning hours of June 21st, much of the region was affected by severe weather. Supercell thunderstorms developed across southeast North Dakota ahead of an approaching convective complex, producing multiple strong, destructive, and fatal tornadoes. This was followed by a powerful line of severe thunderstorms categorized as a derecho, which t...
Flash Flood — Aug 5, 2025
A cluster of thunderstorms produced heavy rain and localized flash flooding over parts of southeast North Dakota during the evening. A wake low developed as this complex moved east with widespread 50 to 55 mph winds reported, and one brief high wind report of 58 mph at Fargo Airport.
Flood — May 21, 2024
Excessive rainfall lead to late May river flooding along the Red River and its tributaries.
Flood — Dec 26, 2023
Rain and above normal temperatures in the southern Red River Valley lead to flood warnings being issued for three sites in southeastern North Dakota. The rain fell on frozen ground, and thus immediately entered the river system.
Flood — Apr 20, 2023
Snowmelt flooding along the North Dakota Tributaries began in early to mid-April, with a few locations persisting into early May.
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 Cass County, North Dakota:
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 Cass County, North Dakota 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.