Introduction to Extreme Heat Events: Extreme heat events can cause a number of health-related problems, including an increase in deaths (mortality) and nonfatal outcomes (morbidity). Yet, almost all of the negative health outcomes from extreme heat can be prevented by taking appropriate measures to ensure that the public stays cool and hydrated during an extreme heat event. As more counties and cities begin to prepare for extreme heat, it is hoped that Kansas will experience fewer heat-related deaths and illnesses. (a) Why Care About Extreme Heat Events? Although most heat-related deaths and illnesses are preventable, a significant number of people die and suffer from extreme heat events every year in the U.S. From 1979 to 2003, more people in the U.S. died from extreme heat than from hurricanes, lightning, tornadoes, floods, and earthquakes combined. From 1999-2003, about 3,442 deaths resulted from exposure to extreme heat in the U.S. The magnitude of deaths and illnesses from extreme heat events is often underreported and little understood by the general public. Extreme heat events do not typically make the news headlines compared to other extreme weather events, such as tornadoes and floods, and they do not leave a lasting trail of infrastructural damage that continuously reminds people of their impact. Therefore, extreme heat events have been called the "silent killers."3 However, in recent years there have been several notable heat waves that have caused a catastrophic number of deaths. In the historic 2003 European heat wave, about 14,800 people in France and about 50,000 people in Europe died from heat related illnesses. In 2010, Russia experienced a heat wave that caused an estimated 4,824 excess deaths in July in Moscow alone.5 The United Nation News Centre reported that this Russian heat wave caused about 56,000 total fatalities across the country,6 likely a result of the combination of extreme heat, smog, and smoke from wildfires.7 Closer to home, more than 700 deaths have been attributed to the 1995 Chicago heat wave. Extreme heat events occur in Kansas; however, it is difficult to know the exact number of deaths and illnesses due to extreme heat events because Kansas does not have an official reporting system for deaths and illnesses attributable to extreme heat.9 A review of mortality records for deaths indicates that 136 deaths were directly attributable to exposure to natural heat in Kansas during the years 2000-2012. This count likely underestimates the full burden of extreme heat on mortality, since it only captures deaths in which exposure to excess heat is explicitly listed as a cause of death on the death certificate. Because heat-related illnesses can cause various symptoms and exacerbate a wide variety of existing medical conditions, the cause of death can be difficult to establish if not witnessed by a physician. (b) Defining Extreme Heat Events: According to the U.S. Environmental Protection Agency, extreme heat events are "periods of summertime weather that are substantially hotter and/or more humid than typical for a given location at that time of year". So, how hot is too hot is based on the usual weather in the area and what is considered normal temperature for the season. How hot it feels depends on location, time of year, and the interaction of multiple meteorological variables (e.g., temperature, humidity, cloud cover, wind). Hotter temperatures earlier in the spring are likely to have more detrimental health impacts than the same temperatures later in the summer because people have not had time to gradually adjust to the warmer temperatures.12 Definitions of an extreme heat event can shift based on location and time of year. Thus, definitions of an extreme heat event need to be sensitive to the variables important for a particular location. Defining an extreme heat event is important for two reasons. First, the National Weather Service (NWS) needs a definition of extreme heat in order to issue a heat advisory, watch or warning. Second, local jurisdictions need to define an extreme heat event locally to determine if and when a heat response plan should be implemented. The following section describes the NWS stations that cover Kansas and how the NWS defines extreme heat events. Chapter 3, "Preparing Kansas for Extreme Heat Events", describes how local jurisdictions define extreme heat events for the purposes of implementing their response plan. Timely forecasting of extreme heat events, transferring the forecast information to the agency responsible for the heat response plan and deciding when to implement the response plan are the first crucial steps in preventing heat-related morbidity and mortality. There are 7 NWS stations serving Kansas. Each NWS station releases heat advisories, watches, and warnings depending on the weather in its own service area. Below is a map of the stations and each service area. The NWS defines extreme heat events by using current and forecasted weather reports. For areas of Kansas, heat advisories, watches and warnings are issued based on a set of temperature thresholds over a certain period of time. See Table 1 below for definitions of heat advisories, watches and warnings for counties in Kansas. The NWS may consider revising its heat advisory, watch and warning definitions based on more current historical meteorological conditions and evidence of heat-attributable adverse health impacts. Local government staff, public health professionals and other organizations that participate in planning and/or providing services for preventing heat-related illnesses should identify the NWS station for their jurisdiction and build relationships with the NWS staff to ensure receiving the most current information available on predicted extreme heat events. The heat index (HI) is an index that combines air temperature and relative humidity in an attempt to determine how hot it feels also known as the apparent temperature. For example, when the temperature is 90^oF (32^oC) with very high humidity, the heat index can be about 105^oF (41^oC). The human body normally cools itself by perspiration, or sweating. Heat is removed from the body by evaporation of that sweat. However, relative humidity reduces the evaporation rate because the higher vapor content of the surrounding air does not allow the maximum amount of evaporation from the body to occur. This results in a lower rate of heat removal from the body, hence the sensation of being overheated. Recorded temperatures in Kansas have ranged from -40 degrees ^oF (Lebanon, February 1905) to 121 degrees ^oF (Alton, July 1934). Temperature extremes for each month are shown in Table 2. Also, the average number of days with temperatures over 90 degrees has been recorded from 1981 to 2010 and displayed in Figure 2. It shows that over 2/3rd of the State had over a month of high temperatures over 90 degrees and the southwestern counties that border Oklahoma, average two months of temperatures over 90 degrees. This map does not depict the overnight minimum temperature averages. If the temperature does not drop overnight, it is more important in a global sense than the record highs. People, mainly those without air conditioning and crops need the temperature to drop during the overnight so that they can sustain the heat during the next day