2. If you should hear the Attention or Alert Signal, turn on a radio or TV set, tune it to any local station, and follow the official instructions being broadcast.
Don't Use the Telephone
Whichever signal is sounding, don't use the telephone to obtain further information and advice about the emergency. Depend on the radio or television, since the government will be broadcasting all the information it has available. The telephone lines will be needed for official calls. Help keep them open.
Learn Your Community's Signals Now
As mentioned before not all communities in the U.S. have outdoor warning systems, and not all communities with warning systems have adopted the two "standard" warning signals.
You should therefore find out now from your local Civil Defense Office what signals are being used, in your community; what they sound like; what they mean; and what actions you should take when you hear them. Then memorize this information, or write it down on a card to carry with you at all times. Also, post it in your home. Check at least once each year to see if there are any changes.
It is possible--but extremely unlikely--that your first warning of an enemy attack might be the flash of a nuclear explosion in the sky some distance away. Or there might be a flash after warning had been given, possibly while you were on your way to shelter.