"flimsy" Southern homes V.S. "heavy" Northern homes
I can't really say. The house I grew up in in Minnesota was over 100 years old before I was born. The siding was 1" thick planks.
Houses here have to meet certain hurricane building codes and are designed with less steep roofs so as to lessen the impact of the wind. As for the strength of the walls and such, wind can be stronger than wood...
-Blast, not helping much