Res 2018-025/adopting the 2018 Hays County, Texas Hazard Mitigation Plan as the official plan of the City; authorizing the inclusion of the City of San Marcos Hazard Mitigation Plan as an appendix; designating the City Manager as the official authorized

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Lightning Lightning: Description According to the 2013 State of Texas Hazard Mitigation Plan Update, lightning is a massive electrostatic discharge between electrically charged regions within clouds, or between a cloud and the Earth’s surface. Lightning: Extent Scale The magnitude of a lightning event can be measured in terms of how many strikes occur within a given time interval. As seen in Table 2.15. Risk Assessment Lightning LALCloud & Storm Development Strikes/15 min 1No thunderstorms.- 2Cumulus clouds are common but only a few reach the towering cumulus stage. 1-8 A single thunderstorm must be confirmed in the observation area. The clouds produce mainly virga (a mass of streaks of rain appearing to hang under a cloud and evaporating before reaching the ground), but light rain will occasionally reach the ground. Lightning is very infrequent. 3Towering cumulus covers less than two-tenths of the sky. Thunderstorms are few, 9-15 but two to three must occur within the observation area. Light to moderate rain will reach the ground, and lightning is infrequent. 4Towering cumulus covers two to three-tenths of the sky. Thunderstorms are 16-25 scattered and more than three must occur within the observation area. Moderate rain is common and lightning is frequent. 5Towering cumulus and thunderstorms are numerous. They cover more than three->25 tenths and occasionally obscure the sky. Rain is moderate to heavy and lightning is frequent and intense. 6Similar to LAL 3 except thunderstorms are dry. (NOAA, 2017) Lightning: Location The entire HMP Update area is exposed to some degree of lightning hazard, though exposed points of high elevation have a significantly higher frequency of occurrence. Since lightning can occur at any location, lightning events could be experienced anywhere within the planning area. Lightning: Previous Occurrences NOAA’s Severe Weather Data Inventory (SWDI) provides the ability to search through National Climatic Data Center (NCDC) archives for data on a county level. SWDI provided historical lightning counts for Hays County from 1986 through 2013. These counts are archived per day. Over the time period, there were 1,667 days with at least one lightning strike in the County (National Climatic Data Center, 2017). As SWDI lightning data is only available on counts per day, extent cannot be determined using LAL Grid classifications as they are determined according to strikes per 15 minute interval. However, the data available did provide the maximum number of strikes within a day of 3,076. Based on the 10,007 days of data presented in the reporting period from 1986 to 2013, there were 1,667 days with at least one lightning event with the County (16.6% of the total days). Those event days resulted in an average of 105 strikes per day with a maximum strike of count of 3,076 in one day. 45