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<br />"B" ratings were given if the reports appeared to be reasonably accurate, but the type of <br />gauge or its placement may have been satisfactory but not ideal. "c" ratings were given to <br />observations that contained useful information but with obvious deficiencies in the quantitative <br />observations. Observations that were obviously erroneous or unusable for other reasons were <br />assigned "0" status. These assessments were used later in the analysis. Some measurements <br />were assigned a "c" or "D" status simply because they came from uncalibrated collectors such <br />as buckets or trash cans. Only 19 of the rainfall observations received were accumulations <br />measured in buckets or other uncalibrated collectors. If thoroughly analyzed, these non-gauge <br />containers could provide useable readings. <br /> <br />In past extreme stOtTns in Colorado, investigators have nonna1ly found very little gauge data <br />from which to detennine rainfall magnitudes and patterns. Therefore, "bucket surveys" were <br />conducted in which extreme rainfalls were deduced from a variety of indirect measurements <br />from receptacles ranging from paint buckets to kiddy pools and stock tanks. Some significant <br />amount of uncertainty has always accompanied bucket surveys. Therefore, the Larimer <br />County stonns of July 1997 may be the most accurately measured and documented extreme <br />rainstotTns in Colorado history to date. <br /> <br />The primary data gathering activities were completed within IS working days after the stonn <br />event. . However, it took several weeks to compile and check all reports, visit selected sites <br />and evaluate data quality. This effort required more than two months of full-time commitment <br />by the Assistant State Climatologist. Several others contributed greatly to the data collection <br />effort including Tun Wirshborn at MSWS and other staff members of the Colorado Climate <br />Center who assisted part time. Based on the initial data gathering activities, a preliminary <br />report was released August 4, 1997 with updates issued August 12 and again on August 29. <br />It then took an addition six weeks for final verification, computer data base development, and <br />the application of radar data. The final set of rainfall maps for the stonn was completed <br />October 9, 1997. Mapping procedures will be described later in this report. The writing of <br />this narrative report then proceeded at a more leisurely pace to accommodate other work <br />responsibilities. <br /> <br />In looking back at this data collection effort, the enthusiastic and willing assistance from many <br />organizations and individual citizens was exceptional. In particular, the successful use of <br />specially authorized wide distnbution electronic mail must be noted. While there was at least <br />a 24-hour delay due to official approval processes in sending out wide-distribution electronic <br />mail requesting rainfall reports, still the method showed great effectiveness as close to 25% of <br />the data collected on this stonn was obtained in this manner. Also, we were able to pose <br />more specific questions in our e-mail request, so that many questions about station location, <br />rain gauge type and exposure and also details about the stonn were answered directly. <br /> <br />Other potentially effective methods of data collection were not attempted such as a special <br />National Oceanic and Atmospheric Administration (NOAA) Weather Radio broadcasts, an <br />official press release to all regional print and voice media, or television announcements via the <br />major Denver broadcasters. Clearly, it could be possible to reach a very large number of <br />potential weather observers in a short time with a well organized and facilitated action plan <br />supported with a prepared and adequately staffed center to receive and process reports. <br /> <br />8 <br />