Colorado Climate Center compiling final data on the Great September Storm of 2013

How much rain fell on Colorado this week? And where? Colorado residents can help the weather experts at Colorado State University answer these questions.

In response to the incredible recent rains and flooding in parts of the state, the Colorado Climate Center will be mapping rainfall totals and graphing hourly intensities for the entire state for the period beginning Sunday, Sept. 8 (as storms first developed over southern Colorado) through the end of the storm later this weekend

"As is typical of Colorado storms, some parts of the state were hard hit and others were untouched. Still, this storm is ranking in the top ten extreme flooding events since Colorado statehood," said Nolan Doesken, State Climatologist at CSU. "It isn’t yet as extreme or widespread as the June 1965 floods or as dramatic as the 1935 floods but it ranks right up there among some of the worst.”

Among the worst, according to Climate Center data, occurred in May 1904, October 1911, June 1921, May 1935, September 1938, May 1955, June 1965, May 1969, October 1970, July 1976, July 1981, and, of course, the Spring Creek Flood of July 1997 that ravaged Fort Collins and the CSU campus.

."Every flood event in Colorado has its own unique characteristics," said Doesken. "But the topography of the Colorado Front Range makes this area particularly vulnerable when the necessary meteorological conditions come together as they did this week."

Data from automated rain gauges maintained by several federal and local agencies will be combined with data from the National Weather Service’s weather radar system and their volunteer Cooperative Observer and storm spotter networks. This will be compiled with rain gauge reports from over 1,000 volunteers who are active participants in the Community Collaborative Rain Hail and Snow Network (CoCoRaHS), which was formed in response to the Spring Creek Flood.

"While this may be the most thoroughly documented storm in our history with so much technology and observational data available, we still have many parts of our state where we don’t know how much rain has fallen," Doesken said. "We realize that many people have weather stations and cameras, and sharing that data could help fill in the gaps to better document the timing of rainfall and its intensity and the patterns of subsequent flooding. Even just a measurement from a bucket that was left outdoors could be helpful — provided you tell us the dimensions of the bucket."

Rain gauge measurements, personal anecdotes about this storm and unique photos that will help to document this storm should be sent to

"This type of information is incredibly important for future construction, engineering, transportation, communication as well as energy and water infrastructure for Colorado,” Doesken added. Floods have happened before and they will happen again, but the more we know about them the better we can prepare for the next one.”

Daily and storm total rainfall patterns will be available on the Colorado Climate Center website Rainfall maps for the entire U.S. and parts of Canada are updated daily at

About CoCoRaHS
CoCoRaHS was initially launched by the Colorado Climate Center at Colorado State University in 1998 as a way to engage the public in helping track and map storms. The network now stretches across the nation, but more volunteers are needed, especially from Colorado’s vast rural areas.

If you are interested in becoming a wet-weather watcher, visit the CoCoRaHS website at Click the Join CoCoRaHS button to sign up as a volunteer. Volunteers must all use the same type of rain gauge for accuracy and consistency.

The Colorado Climate Center has been responsible for documenting climatic conditions observed over all parts of Colorado since weather instruments were first deployed in the state in the late 1800s.