When one thinks of natural disasters, events such as flooding, fires, and hurricanes come to mind. Few will include heat waves in that list, but they are in fact natural disasters. What is even more surprising is learning that heat waves kill more Americans every year than all other natural disaster combined.
The combined number of Americans killed by earthquakes, fires, floods, hurricanes, tornados, avalanches/land slides, sink holes, volcanoes, tsunamis, blizzards, lightning, and hailstorms totals around 200 to 300 people every year. The total number of deaths from heat waves totals around 1,500 people every year. Most of the heat related deaths occur in areas which are not accustomed to regularly experiencing heat. Cities such as Chicago are known more for experiencing frigid cold wind rather than sweltering hot afternoons. These locations do not have air conditioning installed in all buildings like you would find in other locations like Arizona or Texas. Because of these conditions, the poor, the elderly, and the sick all become vulnerable to overheating.
Currently, heat death statistics are not captured in a way that makes it possible to accurately chart heat related deaths over time. However, given that we live in a warming world it is quite possible that Americans will see heat deaths increase over the coming decades.
Most Deadly of the Natural Disasters: The Heat Wave [New York Times, 2002]
2014 National Climate Assessment
One Planet: Heatwaves and climate change [KALW, 2018]