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f Meteorological response The Big Thompson was poorly forecast, detected and warned. In short, the meteorological community was unprepared to provide needed information to the emergency response community. In 1976 forecast techniques for predicting flash flooding were in the experimental stages. No timely flash flood watches or warnings were issued to the public. Poor radar detection of the thunderstorm system contributed to the under-prediction of the danger. Surface weather observation systems could not measure the sub-cloud layer temperature, moisture and wind fields needed to predict the pre-storm flash flood potential. No flood detection networks or effective spotter networks were located in the canyon to provide verification of the flooding or intensity. Communication iinks to the flooded location failed and redundancy in the system did not exist. By comparison the modernization of the National Weather Service has resulted in vastly improved radar-thunderstorm detection by the WSR-88D Doppler radar sites located in Watkins, Pueblo and Grand Junction, Colorado and Cheyenne, Wyoming. These radars provide redundant storm detection capability. Additionally, the radars possess the capability to provide, 1-hour, 3-hour and storm total radar-rainfall estimates for use in assessing the storm's flooding potential. The Big Thompson flash flood triggered two decades of unprecedented research and operational interest in the prediction of flash flooding. Effective research has resulted in the identification of preferred weather patterns, atmospheric structures and types of thunderstorm systems which produce flash floods. Private sector Initiatives in quantitative convective precipitation forecasting have produced reliable methodologies for predicting the amount of rainfall produced by thunderstorms hours before they form. In turn, the future appears to hold the promise of local and regional scale atmospheric modeling of storm formation, movement and rainfall production with no human intervention. The implementation by local governments of ALERT flood detection networks and automated meteorological observation networks or mesonets have provided the means to measure the pre- storm and storm atmospheric rainfall potential and the amount of rainfall and runoff occurring in flood-prone streams and basins. Many, but not all, flood warning systems are coordinated with a well designed plan which is based on hydrological characteristics of the basins at risk and is exercised annually. Lesson learned: Flash floods must be predicted and flash flood watches issued BEFORE the flash flood occurs in order for proactive emergency response to occur. Research has provided reliable prediction solutions and technology the needed detection tools. Flash flood detection. Once a flash flood watch is issued and the thunderstorm system producing the rainfall detected by radar, verification of the flooding event quantitatively is very desirable. Precious time was lost July 31, 1976 while forecasters tried in vain to verify that a flash flood was in progress to evoke an effective warning. No timely warnings were issued. The implementation of countless flood detection networks world-wide have proven that they can provide the verification response needed if they are in place and working. Flood detection networks are expensive and require a considerable investment in man-power and dollars to implement and maintain. Flood detection networks are especially effective in slow response basins ( > 3 hours response time) in evoking a warning response. However, in fast response ( < 3 hours) basins in urban and mountainous areas, flood detection networks can not provide adequate warning. Even in these areas they can provide a quantitative grasp on the magnitude, duration and location of the flash fiood. In the absence of flood detection networks, 3