The 2013 Colorado Floods in Boulder County


Floods are acts of God, but flood losses are largely acts of man.

-- Gilbert F. White

In September 2013, Colorado experienced unprecedented rainfall and massive, widespread flooding across the northern portion of the state. The extent of the flood can be seen below:

View Larger Map FEMA's Situational Awareness Viewer. If you click through to the full-screen version, you can toggle different layers, including geo-located pictures of the flood event and flood inundation extents. Because of the large and complex nature of this tool, you may have to double click on it to load some features, and using the "View Larger Map" is recommended.

This site is the Natural Hazards Center's revised version of the Gilbert White Boulder Creek Flood Notebook. The site contains contributions from leading scholars as well as practicioners involved with the response and preparation to the flood event. The essays include:

  • An introduction by David Butler that details what the Boulder Creek Flood Notebook was, and how the September 2013 flood event differed from what Gilbert had envisioned.
  • An collection of reminiscences from Dennis Mileti, a student of Gilbert's who followed in his footsteps to direct the Natural Hazards Center, about what he learned from Gilbert and how that impacts how he studies disaster warning systems, including those invoked during the Colorado floods
  • A post from Bob Henson of the University Corporation for Atmospheric Research (UCAR) that provides an overview of the rain and flood event as well as notes on just how historic the floods were.
  • An essay from Kevin Stewart of the Urban Drainage and Flood Control District about what was learned from the 1976 Big Thompson flood and the improvements to warning systems in the almost 40 years since.
  • An account from Dan Eamon, a Longmont Emergency Manager, of his town's response to the flooding that includes both what went right and lessons learned.
  • And research carried out since the floods in the Natural Hazards Center's Quick Response program.

The recovery from the floods is ongoing, and as such so is this site. It will be updated with new essays, new media, and more information, so check back often. If you think something needs correcting or you would like to contribute, contact us at or find us on Twitter and Facebook.