Oy, but I forgot you had such big cockroaches in other parts of the world. I am sure that makes a difference. We have teeny cockroaches by comparison - average 3/4 inch & smaller in Montréal. Oddly, they are not the blight you hear about in other countries (maybe it's our spiders )

I think it has to do with the cold. Not a big skier your average cockroach. Mostly just freezes up & dies. Not like flies or spiders that freeze solid and just thaw out like nothing happened in the springtime.