Extreme heat is a silent killer. From time to time, we hear about shocking cases of football players and other athletes who die suddenly while exerting themselves on hot days. Those deaths are certainly tragic, but statistically they are very rare. Most deaths from extreme heat are in older people, who frequently die alone inside their homes. They often die slowly, as the heat creeps up to and sometimes past body temperature, especially when heat domes park themselves over cities and keep the temperature high all day and all night. When such deaths happen, they rarely make the news. Of…