Note: I do not recommend storm chasing by the general public; quite the opposite. I'm posting this for emergency managers and law enforcement.
There is a web site dedicated to learning more about the May 31, 2013, El Reno, Oklahoma super tornado. That storm is one of the most intense ever recorded (note: I am not saying it was the most intense ever to occur).
There are many in and outside of meteorology that wish to contribute to our knowledge of these storms by conducting scientifically valuable storm chases. The best checklist I have seen is on that site and it is located here.