Flood

Flood season begins April 1 and it’s important that CU-Boulder students, faculty and staff know what to do in the event of flash flooding. The city of Boulder provides information on risks specific to post-flood conditions as well as the top eight personal preparedness tips to help residents get ready for flood season. Below are links to areas on campus that are within flood zones.

Monthly flood siren tests will begin on Monday, April 6, and continue on the first Monday of the month through August. During an emergency, the sirens are used to alert residents to potential danger from a flood or other immediate threat. Siren tests ensure that all systems and procedures are working properly during the season of peak flood danger. The tests also promote public awareness of the warning sirens located throughout Boulder County.

Flood Maps

If a flash flood warning is issued, heed all instructions and stay away from Boulder Creek and other areas where flooding is occurring. Climb to higher ground immediately and avoid drains, ditches, ravines and culverts.

East Campus Flood Zone

Family Housing Flood Zone

City of Boulder Flood
Hazard Zones (interactive)

Know

Flash floods are short-term events, occurring within 6 hours of the causative event (heavy rain, dam break, levee failure, rapid, snowmelt and ice jams) and often within 2 hours of the start of high intensity rainfall. A flash flood is characterized by a rapid stream rise with depths of water that can reach well above the banks of the creek.

In Boulder, flash floods are often the result of strong afternoon thunderstorms over the foothills during the summer months which produce short, but heavy rainfall.  Boulder may also experience flash flooding as a result of heavy rainstorms when combined with snowmelt run-off in the springtime.

All campus affiliates are encouraged to become familiar with the different notifications the National Weather Service will issue regarding the potential for flash flooding.

  • A flood advisory means that thunderstorms have produced heavy rainfall that may result in ponding of water on roadways and in low-lying areas, as well as rises in small stream levels, none of which pose an immediate threat to life and property.
  • A flash flood watch indicates that conditions are favorable for flash flooding. During a watch, normal campus activity should continue, but you should tune in to local media and monitor the situation. Be aware of your location relative to streams and creeks. Be prepared to take immediate action if a warning is issued for your area.
  • A flash flood warning means that flooding is imminent or is already occurring. You may only have a few minutes to seek safety, so take immediate action by moving to higher ground on foot as soon as a warning is issued.

Flash floods can occur rain or shine. Understand the warning signs of a potential flash flood including; sudden, heavy rains, a sudden increase in creek level, or the creek water begins to become muddy or debris-filled.

The CU Boulder main campus sits atop a hill out of the Boulder floodplain, and therefore out of the danger of flash flood waters. However, portions of East Campus and Family and Graduate Housing are located within the floodplain. Those who work or reside in these areas should familiarize themselves with the safety actions they should take when a flash flood warning is issued. Whether you should shelter-in-place or evacuate depends on which campus building you are in on East Campus or in the Family Housing area. Use the maps linked to the right for more information on these locations.

Campus affiliates who are registered CU Alert users will receive an e-mail or text message informing them of a flash flood warning affecting the campus. By registering for CU Alerts, you will receive quick notification when a flash flood warning is issued that affects the campus. During the emergency, updates will be sent out as appropriate, and an all-clear may be provided by University officials once the danger has passed. Please click here to sign up to receive alerts.

Outdoor warning sirens are located throughout the city of Boulder and are sometimes used to inform residents that a flash flood is imminent or occurring.  The sirens are tested on the first Monday of every month between April and August.

Flash flood warnings will also be announced by local media outlets such as radio, television, and online news sites.

If a flash flood warning is issued for the city of Boulder heed all instructions and stay away from areas where flooding is occurring.  Even if there is no other indication that a flash flood may be occurring, immediately take the following actions to protect yourself from harm when you receive notification of a flash flood warning.

If you are outdoors:

  • If you are outdoors and near a creek or stream when a warning is issued, climb to higher ground on foot immediately. Avoid drains, ditches, ravines, and culverts.
  • Do not attempt to outrun a flood in a vehicle—cars will float in as little as one foot of water. Over half of all flash flood fatalities occur in vehicles.
  • If your vehicle stalls or is surrounded by water, abandon it and move to higher ground on foot.
  • If you are unable to move to higher ground, seek shelter on the upper floors of a sturdy building.
  • Remain alert for instructions and updates as they become available from emergency personnel and University officials.

If you are indoors:

  • In campus buildings, follow your building’s instructions regarding evacuation/shelter-in-place for flash floods.
  • Move to the highest floor possible, or follow the flash flood procedures for the building you are in. Remain in a sheltered location until an all clear has been provided by public safety officials.
  • If you are in a main campus location, affiliates are encouraged not to leave campus until flooding has subsided and you have been told by public safety or University officials that it is safe to leave the area.
  • Use caution after a flash flood as risk of electrocution, dangerous debris, and other hazards may exist.
  • Use special caution at night because a flood danger is more difficult to recognize.
  • In the event of a flash flood, or any other campus emergency, visit the CU Boulder homepage for the most accurate, up-to-date information.
  • Check the Boulder Office of Disaster Management website for up-to-date emergency information regarding the larger Boulder community.