What is the 30 30 rule for lightning?

Related questions

1. Does it rain in a tornado?
2. What are weather squalls?
3. Can a tornado happen without clouds?
4. What causes thunder?
5. Why is thunder loud?
6. Can lightning kill you in a car?
7. What is a snow shower?
8. What state has never had a tornado?
9. What does snow squall warning mean?
10. Where is Tornado Alley?

Tags

1. #resuming
2. #seeing
3. #threat
4. #minutes
5. #activities
6. #takes
7. #seconds
8. #enough
9. #after
10. #storm
11. #thunder
12. #before
13. #lightning
14. #outdoor
15. #flash