Boulder Guide to Flooding | City of Boulder

Boulder Flooding Information

The city of Boulder rests at the base of the Rocky Mountain Foothills and is home to Boulder Creek, its 14 tributaries and Boulder Slough (diverted water from Boulder Creek to satisfy irrigation company water rights). Due to its geographic location and features, the city of Boulder has the highest risk of flash flooding in the state of Colorado.

Many neighborhoods throughout the city experience flooding during storm events, and some are at a higher risk to extreme flooding because they are located near a major drainageway. The City of Boulder encourages all residents to be aware of their flood risk and to take the necessary precautions to help protect life and property.

City of Boulder Floodplain Information Map

The map shows floodplains, conveyance zones, critical facilities, elevation certificates, and various flood-related FEMA information.

To find out if you are in a Special Flood Hazard Area (floodplain), go to the map below and click the search icon (magnifying glass) to enter your property address.

Floodplain Information Map

Be Aware, Be Vigilant, Be Safe

Office of Disaster Management Tests

During flood season, the Office of Disaster Management will test the emergency sirens located throughout the city/county. Tests of this system occur on the first Monday of each month during flood season and can be heard at 10 a.m. and again at 7 p.m. The purpose of the test is to verify the system is working as intended, and is meant to be heard by community members outdoors who may not have immediate access to emergency warnings otherwise. They are not intended to be heard necessarily by community members located inside.

How to Prepare for Floods

Emergency Alerts

Sign up for FREE emergency alerts at BoCo911Alert.com. You can get alerts via home, work, and cell phones, text messages and email. When a flood watch or warning is issued for your area, find more information by tuning to local news and visiting www.boulderoem.com.

Emergency Kit

Prepare an emergency kit.

Flood Insurance

Don't delay purchasing flood insurance to protect your property. There may be a 30-day waiting period before your new policy becomes active.

Purchase flood insurance to protect your property.

Discharging Groundwater

Learn what you need to know to be safe, resilient and protect your property

FEMA FloodSmart

Be Flood Smart www.FloodSmart.gov

Protect Natural Floodplain Functions

If you plan on doing any work on your property you may need a floodplain/wetland permit.

The city has adopted regulations for development within streams, wetlands, and water bodies to help preserve and protect these natural resources.

Flood Watches and Warnings

The Office of Disaster Management tests the city's emergency warning system on the first Monday of each month during Flood Season (Apr - Sept).
Sirens are tested at 10 a.m. and 7 p.m.
The sirens are intended as a resource for community members outdoors during an emergency event who may not have easy access to additional alert notifications.
They are not intended to be audible for community members indoors.

Flash Flood Watch	Flash Flood Warning
Weather conditions may cause flash flooding in the specified area. Be ready to move to higher ground during heavy rainfall.	Flash flooding is occurring or is imminent in the specified area. Move to higher ground immediately. In some locations and situations, it may be safest to shelter in place on the upper floor of the building.