Floods have played a major role in shaping the history and location of Fort Collins. In 1864, a massive flood roared down the Poudre River, destroying the original Camp Collins military post located near present-day Laporte. The settlement was eventually rebuilt on higher ground near Old Town and renamed Fort Collins.

100-Year Storm

A 100-year storm is the amount of rainfall measured at a certain location, during a specified length of time, that has a 1% chance in any given year of being equaled or exceeded. 
It is normal in Colorado to experience many storms that locally equal or exceed rainfall defined as the 100-year storm.
It is likely that between 100 and 300 "100-year storms" occur somewhere in Colorado in a typical year.

Odds of Occurrence

  • Structure in the 100-year floodplain being flooded in any given year:      1 in 100
  • Matching 1 number plus the Powerball in the Powerball lottery:       1 in 124
  • Structure in the 500-year floodplain being flooded in any given year:      1 in 500
  • Annual chance of being killed in a car accident if you drive 10,000 miles a year:     1 in 4,000
  • Being struck by lightning:     1 in 600,000

1997 Flood

This July marks the 20th anniversary of the July 28, 1997 flood, the most damaging flash flood to ever hit Fort Collins.  Flooding occurred when 14.5 inches of rain fell over a 31-hour period. This is the equivalent of our average yearly rainfall! The flood resulted in five deaths and an estimated $200 million in damages.
Torrential rains began Sunday night, and dumped 4-6 inches of rain in the area. The next night, with the ground already saturated, a second round of even heavier storms formed in the same area. Meteorologists later described these storms as almost tropical in nature. More than 10 inches of rain fell from 5:30–11 p.m. the second night.
The flooding swelled tiny Spring Creek into a raging torrent resulting in the deaths of five people, $200 millions dollars in damages, 2,000 homes and businesses damaged, the destruction of two fully occupied residential trailer parks and a derailed freight train.
The Colorado State University campus also suffered hundreds of millions of dollars in damage to buildings, including the Morgan Library, which lost much of its inventory of books and journals.

September 2013 Flood

From Sept. 9-16, 2013, Colorado experienced one of its most extreme rainfall and flood episodes in recorded history. Certain locations in Fort Collins received up to 12 inches of rain, resulting in the largest flood event on the Poudre River in Fort Collins since 1930.
Due in part to a comprehensive floodplain management program that includes regulations, open space preservation, capital projects, public education and flood warning systems minimal damage to structures occurred. The benefits of these efforts were captured in a 2014 Colorado Water Article 2014 Colorado Water Article

Flood Warning System: Rainfall and Streamflow Data

Since 1999, Fort Collins Utilities has operated a Flood Warning System to notify the public and emergency services about real-time information on rainfall, stormwater run-off and weather conditions and early detection of hazardous conditions.

Protect the Floodplain...It Protects You

Flooding is a natural process. A healthy riparian ecosystem relies upon frequent inundations to survive and thrive. Along the Cache la Poudre River many riparian areas have been preserved, including Gustav Swanson Natural AreaColorado State Environmental Learning Center, and Kingfisher Point Natural Area. In 2014, McMurray Natural Area underwent a major restoration effort.
Floodplains help reduce flood damage by allowing water to spread over a large area. This reduces the speed of flood water and provides flood storage to reduce peak flows downstream. The City of Fort Collins owns a number of parcels along Spring Creek, Fossil Creek and the Cache la Poudre River, permanently preserving these areas as riparian open space and reducing the flood hazard.

Building Resiliency

Fort Collins has a long history of proactive stormwater and floodplain management. Prior to the 1997 flood numerous mitigation projects on Spring Creek, including acquisition of 30 mobile homes, nine residential structures, a retirement home and a business. It is estimated that an additional 98 lives could have been at risk in 1997, if it wasn’t for these projects.
Fort Collins Utilities continues to implement flood protection measures to help the City be more resilient to floods. Many of these improvements have already shown their benefits, by protecting our community during storm events over the past 20 years.

Basin by Basin

The Stormwater Master Plan determines drainage improvement projects throughout the city. The Plan addresses stormwater quality from rainfall runoff and  identifies stream restoration projects that protect the city's watersheds.
Streams in Fort Collins have changed drastically due to urbanization. Poor water quality from rainfall runoff can lead to erosion in streams and harms macroinvertebrates, the primary food source for fish and other aquatic animals.
Fort Collins is divided into 12 drainage basins. Each basin master has identified problem areas and planned improvements to mitigate damages

Everyone Has a Flood Risk

All rivers, streams, tributaries and canals-regardless of size-have the potential to flood. Urban street flooding is also a hazard. City floodplain maps can help demonstrate where the greatest risks are and whether a property is within a floodplain.
Fort Collins floodplain residents receive one of the lowest flood insurance rates in the country as a result of our Floodplain Management Program, which is one of only 5 communities achieving top-ratings by the Federal Emergency Management Agency.

Before a Flood

  • Purchase flood insurance
  • Make a plan
  • Document your belongings
  • Store valuables in higher locations
  • Sign up at leta911.org

During a Flood

  • Don't drive through floodwater
  • Move to upper floors or higher ground
  • Don't walk through flowing water
  • Listen for emergency updates
  • Turn off power and gas

After a Flood

  • Check for structural damage
  • Document all damage
  • Remove wet items
  • Get a floodplain use and building permits before making repairs
  • Contact your insurance agent and file a flood insurance claim