![A tornado outbreak killed 64 people in Pennsylvania 35 years ago. We still know terrifyingly little about the storms. A tornado outbreak killed 64 people in Pennsylvania 35 years ago. We still know terrifyingly little about the storms.](https://www.inquirer.com/resizer/5D0aA3Pt5hf-eQANZKRwoV18mOw=/arc-anglerfish-arc2-prod-pmn/public/FQ7PSG2YV5A2JK27U2ZAKILZXA.jpg)
A tornado outbreak killed 64 people in Pennsylvania 35 years ago. We still know terrifyingly little about the storms.
![The Five Deadliest F/EF5 Tornadoes on Record | The Weather Channel - Articles from The Weather Channel | weather.com The Five Deadliest F/EF5 Tornadoes on Record | The Weather Channel - Articles from The Weather Channel | weather.com](https://s.w-x.co/util/image/w/GettyImages-114520248-joplin.jpg?v=at&w=320&h=260)
The Five Deadliest F/EF5 Tornadoes on Record | The Weather Channel - Articles from The Weather Channel | weather.com
![The Five Deadliest F/EF5 Tornadoes on Record | The Weather Channel - Articles from The Weather Channel | weather.com The Five Deadliest F/EF5 Tornadoes on Record | The Weather Channel - Articles from The Weather Channel | weather.com](https://s.w-x.co/util/image/w/Burt-EF5s-fig0-930px.jpg?v=at&w=400&h=400)
The Five Deadliest F/EF5 Tornadoes on Record | The Weather Channel - Articles from The Weather Channel | weather.com
![2018 was one of the least active years on record for US tornadoes; No twister rated EF4 or higher | AccuWeather 2018 was one of the least active years on record for US tornadoes; No twister rated EF4 or higher | AccuWeather](https://cms.accuweather.com/wp-content/uploads/2018/12/timmer-tornado.jpg)