Answer: The most common tones produced by sirens in the United States are "alert" (Steady) and "attack" (wail). ... Attack Warning – A 3 to 5 minute wavering tone on sirens or a series of short blasts on horns or other devices. The Attack Warning signal means detection of an actual attack or accidental missile launch. The sirens are usually for the people surrounding the area to let them know that they need to evacuate immediately.
I hope this helps
~Princess <3
I believe they had a plane with cameras that tools pictures and they saw in on there
