stations in time for citizens to get into shelters or at least take
cover. This warning time might be as little as 5-15 minutes in some
locations, or as much as an hour or more in others.

How you received warning of an attack would depend on where you happened
to be at that time. You might hear the warning given on radio or
television, or even by word-of-mouth. Or your first notice of attack
might come from the outdoor warning system in your own city, town or
village.

Many U.S. cities and towns have outdoor warning systems, using sirens,
whistles, horns or bells. Although they have been installed mainly to
warn citizens of enemy attack, some local governments also use them in
connection with natural disasters and other peacetime catastrophes.

Different cities and towns are using their outdoor warning systems in
different ways. Most local governments, however, have decided to use a
certain signal to warn people of an enemy attack, and a different signal
to notify them of a peacetime disaster.


THE STANDARD WARNING SIGNALS

The two "standard" signals that have been adopted in _most_ communities
are these:

THE ATTACK WARNING SIGNAL. This will be sounded only in case of enemy
attack. The signal itself is a 3- to 5-minute _wavering sound_ on the
sirens, or a _series of short blasts_ on whistles, horns or other
devices, repeated as deemed necessary. The Attack Warning Signal means