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research Appraisal District records and other sources to identify property owners located downstream of dams and spillways and to create the Emergency Response Database. I Mitigation Action F-6, Improve Flood Warning in Hays County, is described in Section 6.0 and recommends that flood warning systems be installed in selected 'High Hazard" dams. The fourteen (14) "High Hazard" Dams identified above are addressed in Mitigation Action F-6. 2.4 Tornado Hazard Identification: Tornadoes are considered to be the most erratic, most unpredictable and most violent of all atmospheric storms. Winds in the strongest of these storms can exceed 250 miles per hour. By definition, a tornado is often described as a violently rotating column of air, in contact with the ground, either pendant from a cumuliform cloud or underneath a cumuliform cloud, and often (but not always) visible as a condensation funnel cloud. Significant damage can occur even when the condensation funnel does not r~ach the ground. Tornadoes generally fall into two types of categories. A Type I tornado is associated with thunderstorms containing a larger parent circulation, often called a "supercell". Large and violent tornadoes, almost without exception, fall into this class. The generally weaker Type II tornado (or non-supercell tornado) is a smaller circulation that forms along windshift lines and other boundaries without a vigorous parent circulation. The intensity of these storms is rated using the Fujita Scale of wind damage, which was developed decades ago in response to I identifiable trends in structural failures due to wind. A tornado is given a Fujita rating of 0-5, based on the most intense damage along its path. Wind velocities necessary to produce the particular damage are often associated with the Fujita category, but that practice is often misleading at best. The Fujita wind estimates are intended to be based upon the expected damage to a well-built residential structure. Poorly built structures can suffer significant structural damage under lesser winds than the Fujita Scale might suggest.. Tornadic storms can occur anywhere throughout the United States, but they are far more frequent in a zone that stretches from northern Texas through Oklahoma and into Nebraska, commonly called "Tornado Alley." The North Central Texas region is the largest metropolitan area in Tornado Alley. Tornadoes seem to occur more frequently in Tornado Alley because recent research suggests that Tornado Alley is a breeding ground for conditions which are ripe for tornado formation-high instability, strong veering (turning) of the wind direction in the lowest half mile of the atmosphere, and often in the vicinity of weak boundaries. The flat terrain enhances rapid movement of air, while high humidity of the Gulf Stream further induces instability in the atmosphere. Tornadic stOlms can occur at any time of year and at any time of day, but they are typically more common in the spring months during the late afternoon and evening hours. A typically smaller, high frequency period can emerge in the fall during the brief transition between the warm and cold seasons. The Hays County Mitigation Planning Committee classified tornado as "major" in severity and I "likely" in frequency. Hays counly, Texas Miligalion Plan 61