Enter any address in Boulder County, Colorado to see its FEMA flood zone
Flash flooding from intense rainfall events is the dominant flood character in Boulder County. Over the last 30 years, NOAA Storm Events data shows 31 flash flood events occurred, resulting in 4 fatalities, compared to 6 general flood events. For example, flash flooding impacted the Calwood and Cameron Peak burn areas in July 2021, with up to 2.5 inches of rain falling in one hour, and a significant debris flow surged down Geer Canyon in June 2021.
National Flood Insurance Program (NFIP) claims data indicates that properties in Zone A have experienced the most claims, with an average payout of $36,665 and an average water depth of 5.3 feet. Properties in Zone X also show a substantial number of claims. Homeowners in Zone A, and those in Zone X with higher water depths, should pay the most attention to flood risk.
Summary generated from NOAA storm narratives and NFIP claim data for this county. Not predictive.
13 NOAA storm reports from this county describe what happened, in the words of the meteorologists who were there.
Boulder County, Colorado has recorded 37 flood-related events since 1996 according to NOAA's Storm Events Database, including 31 flash floods and 6 river or area floods. The county has received 19 federal disaster declarations, 6 of which involved flooding or coastal storms. Enter any address above to check its FEMA flood zone designation.
FEMA Disaster Declarations (1969–2024)
Source: OpenFEMA Disaster Declarations Summaries.
| Declaration | Type | Date |
|---|---|---|
| Stone Mountain Fire | Fire | Jul 30, 2024 |
| Marshall Fire | Fire | Dec 30, 2021 |
| Wildfires And Straight-line Winds | Fire | Dec 30, 2021 |
| Calwood Fire | Fire | Oct 17, 2020 |
| Covid-19 | Biological | Jan 20, 2020 |
| Covid-19 Pandemic | Biological | Jan 20, 2020 |
| Severe Storms, Tornadoes, Flooding, Landslides, And Mudslides | Flood | May 4, 2015 |
| Severe Storms, Flooding, Landslides, And Mudslides | Flood | Sep 11, 2013 |
| Four Mile Canyon Fire | Fire | Sep 6, 2010 |
| Olde Stage Fire | Fire | Jan 7, 2009 |
NOAA Storm Events Database (1996–2025)
Source: NOAA National Weather Service Storm Events Database.
| Type | Date | Damage |
|---|---|---|
| Flash Flood | Jul 31, 2021 | 10.00K |
| Flash Flood | Jul 30, 2021 | 20.00K |
| Flash Flood | Jun 27, 2021 | 10.00K |
| Flood | May 8, 2015 | 100.00K |
| Flash Flood | Jun 4, 2015 | 15.00K |
| Flash Flood | Sep 12, 2013 | 0.00K |
| Flood | Sep 12, 2013 | 0.00K |
| Flood | Sep 12, 2013 | 297.00M |
| Flood | Sep 11, 2013 | 0.00K |
| Flash Flood | Sep 11, 2013 | 0.00K (3 deaths) |
Flash Flood — Jul 31, 2021
Heavy rain in the Calwood burn areas caused flash flooding from Geer Canyon Drive to CO 36.
Flash Flood — Jul 30, 2021
Flash flooding occurred on Tonahutu Creek. Trees, mud and debris shut down Grand Lake's hydro plant. Approximately 50 downed trees piled up at the plant's head gate and ash and mud filled the ditch leading to another gate. Another flash flood impacted CO-125. Additional flash flooding occurred in the Calwood and Cameron Peak burn areas, where up to 2.5 inches of rain fell in one hour. In E...
Flash Flood — Jun 27, 2021
A thunderstorm produced heavy rain and flash flooding in the Calwood burn area. Law enforcement reported a 3 to 4 foot surge of debris and water flowing down Geer Canyon. |The debris flow impacted stretches of Geer Canyon Drive and the lower part of Geer Canyon.
Flood — May 8, 2015
Areal flooding developed along the Cache La Poudre and South Platte River Basins as a combination of heavy rainfall and spring runoff unundated the region. The Cache La Poudre reached flood stage from the 10th the the 14th. The South Platte rose above flood stage at Kersey from the 9th to the 15th. A few landslides were initially reported along the Saint Vrain River with minor flooding south...
Flash Flood — Jun 4, 2015
Severe thunderstorms broke out across Boulder, Denver, Elbert, Jefferson and Larimer Counties. Two large and long lived tornadoes developed in Larimer County near Berthoud and near Simla in Elbert County. The tornado that occurred along the Boulder and Larimer county line was rated an EF3 at it's highest damage point, with maximum winds estimated at 135 to 140 mph. The path length was 6 mile...
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 Boulder County, Colorado:
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 Boulder County, Colorado 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.