Final answer:
The decrease in tornado fatalities since the 1950s is due to improved technology and earlier warnings, stronger building codes and construction, and better education and communication methods.
Step-by-step explanation:
The observed decrease in the annual average number of fatalities due to tornadoes since the 1950s can be attributed to several advancements and changes in society. Improved technology has led to better detection and forecasting of severe weather events, enabling earlier warnings and more time for people to seek shelter. Enhancements in building codes, construction materials, and design have resulted in stronger structures less likely to collapse during a tornado.
Additionally, broader education about tornado safety and preparedness has informed the public on how to protect themselves during such events. The spread of information through mass media and communication tools like the internet and smartphones has also played a crucial role in disseminating warnings quickly and effectively.