This is due to a power reset and when most older panels start they trigger the alarm for a half second

Was that a spectralert classic?

I remember once we had a power outage at my college during a storm and so I was walking around campus only to discover the theater alarms were going off. Weird, because it's a newer system. Then again, the power outage itself was what tripped the alarm.

1:01 1:11

The alarms themselves dont require that much voltage about 15 volts the lightning may have produced that and made them activate whenever the lightning struck causing the control panel to go into "trouble" and beep to let the owner of the building know that something has tripped

How does the lightening trip the fire alarm? Did it hit the junction box or something? I'm really glad that didn't happen in my dorm over the past year. During one storm we had lightening hit several of the light poles from the sports fields across the street from my building