Hi,
I too get the alarm bell, thought the house was on fire, LOL, then realised it was the TOA/Google Earth software sounding a bell because of strikes within the alarm zone - yes that's the important point, just because you can hear thunder does not mean that the storm is within your zone. As I recall, the zone size is small, it's like 10km all around, so unless the storm is very close or overhead, the alarm won't sound. Just as well really, it could get pretty annoying otherwise.
Nick. dw7240.com.