The verb that describes an alarm making its alarm sounds is "go off". Car alarms, fire alarms, and even your alarm clock at home all "go off":

I was in class when the tornado alarm went off.

I usually wake up before my alarm even goes off.

Other things that are similar to alarms also "go off":

When he said that, warning bells went off in my head. Why did he want to know about that?

Did you hear the gun go off?

His temper is like a time bomb waiting to go off.