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While this was not the case, our relatively disorganized but enthusiastic effort still appears to have been highly effective. Database Development As storm reports were coming in and being processed, other office staff developed a simple spreadsheet database to enter all reports for later analysis. One of the complicating factors in developing this database was the irregular observation intervals. Some observers only recorded total rainfall for the entire 2-day period. Others read and emptied their gauges once each day at the same precise time. There were also some very motivated individuals who made a special effort to read their gauges several times during the storm and note the time of each reading. This information, along with even more detailed reports from the few recording gauges, made it possible to develop a thorough time history of rainfall throughout this exceptional event. The resulting database was set up to accommodate any time interval measurement from hourly values on up to simple storm totals. Each report was assigned a precise latitude and longitude using special mapping software currently available. Accurate coordinates were critical for objective plotting and computer analysis of rainfall. Colorado Climate Center staff also made use of a Global Positioning System (GPS) unit to pinpoint observations coordinates. Visiting each site with the GPS proved to be much more time consuming and no more !lCCIJI1lte than using mapping and address software, so most of the coordinates were found using the computer without leaving the office. Storm Analysis and Rainfall Mapping As the database was assembled, analysis and mapping began. Figure 2 shows the locations of rainfall reports that were gathered in the weeks immediately following the Fort Collins flood. The majority of these reports came from the immediate Fort Collins area, but others were scattered around the county. A few data points from adjacent counties were included to more clearly define the limits of this rather smaI1 storm system. In some portions of the Fort Collins area, data reports were numerous with several reports per square mile. Rainfall reports were very sparse for other areas, particularly immediately west and southwest of Fort Collins. The wide variety of rainfall measurements: recording rain gauges, official weather stations, hobby weather watchers, casual onlookers, mixed with uncalibrated bucket measurements, produced an awkward data set. Varied measurement intervals ranging from detailed minute- by-minute reports to single storm totals added another dimension of complexity. But while posing a great challenge, these diverse data also contained additional valuable information. The combination of overlapping measurement intervals from a very large number of locations sometimes only blocks from each other, offered an opportunity to extract detailed information about the storm's time history. This would not have been an issue had the storm been just one downpour. However, by looking at the data, it was very evident that there were several distinct periods of rain, some locally very heavy, that fell during the 24 hours prior to the 9