As I live in a country that’s rich both in storms and power outages, I couldn’t stop noticing these two strange coincidences:
- some time before the storm breaks loose and rain starts to fall, when there’s only lightning and such, car alarms seem to start randomly, but usually more than one at a time.
- also, when there’s a power outage, in the very moment when power is cut down, car alarms start again. :dubious:
I think it’s pretty obvious this has some connection to electricity and electric fields, but I’, really curious if anyone has any idea why these things happen.
Thunder can set off both in car intrusion sensors as well as vehicle motion detectors. If you ever go to San Francisco’s International airport the jumbo jets take off right over the long term parking. Every time a 747 takes off five or six car alarms will go off in the parking lot. Lots of people get back from vacation to find they have a dead battery.
As far as hearing them when the lights go out, I suspect that they have been going off for a while, and the normal sounds of the household are masking them (fridge, washing machine, dishwasher, TV, Radio, A/C etc) When all of that background noise stops all at once, you hear the only noise left, the car alarms.
When the power goes out during a storm, it’s usually because either lightning hit something and destroyed it or caused excessive current somewhere, or it’s because wind blew something around to cause a fault (like blowing one power line into another, or blowing a tree branch onto the lines, etc). The sound from nearby thunder is enough to set off a lot of car alarms. Wind that is strong enough to blow power lines around or blow tree limbs into lines is also strong enough to shake a car which will also often set off the alarms.
The electrical charge build up that eventually causes lightning tends to go around the outside body of the car (google Faraday Cage if you want to know why). It generally doesn’t affect any of the electronics inside the car, including the car alarm.
I used to work at a defense contractor next to BWI airport. On rare occasions, the wind would be facing a certain direction and they would take the big jets off over our parking lot. Every time a 747 went over the parking lot, so many car alarms would go off that it almost sounded like a big field of very loud crickets.
Thank you for clearing things up! Your explanations seem pretty plausible I’m pretty sure you’re right.
What is still a little unclear is the power outage part. I wasn’t talking about outages that happen during the storm, but during the calmest of nights. Car alarms really piss me off, so I don’t think I didn’t hear them, judging by the relative quietness of the neighborhood.
So maybe there’s something more, possibly connected to the streetlights or something. Or maybe I’m just stubborn :smack:
Lots of people get back from vacation to find they have a dead battery. 
