What is a destructive thunderstorm warning ?

A severe thunderstorm warning indicates the warned area is in impending danger from hail or wind speeds meeting warning criteria 

Should I be worried about a severe thunderstorm ? 

If the warning includes your neighborhood or work place, you should take immediate action to protect your life and the lives of others 

Severe thunderstorms can produce large hail and damaging winds. Tornadoes can and occasionally do accompany severe thunderstorms. 

What you should do if you are outside when lightning is around ? 

Crouch down in a ball-like position with your head tucked and hands over your ears so that you are down low with minimal contact with the ground 

What season are thunderstorms most common ?