I will second this, but also use it to say that if you do not have one and are in areas where severe weather occurs you should have a weather radio with S.A.M.E. technology and an alarm that will wake the dead
Ours went off three times yesterday, high wind and flooding danger and we are no where near where tornadoes hit.
I decided on a Recom
http://www.reecominc.com because it shuts itself off after each alert (still monitors) and there have been many nights where it will wake us up and I do not want to come down stairs to shut it off. Ours is set to catch all alerts because it goes with us in Compass Rose, this after a VERY stormy Boogie in the Hills and Tornado near by. They can however be programed with county information to limit where you get alerts from.
This is one aspect of government that works well and can save your life.