Lee Michaels wrote:
....

I assume if big storms happen there that building codes would have been
strengthened recently. Older houses would not have the improvements.
....

Actually, it's interesting in that often the very old survive better
than new as construction in the '20s often was much stouter than tract
housing of the post-war era which tended to get faster/cheaper
continuously until, as you suggest, changes in local Codes forced some
areas back into better-suited detailing (as Swing notes as well)...

I was prompted to add this note by his comment and the previous comment
on shape affecting damage as well as the age...

In the Greensburg, KS, EF-5, one of the strongest ever observed, it
completely flattened 95% of the entire town (path was dead-center of
town, 1-1/2 mile wide destructive funnel). The few dwelling structures
that did stand at all in the path were a handful small, square one-story
hip-roofed houses and a single 2-story expensively built '20s-era full
brick construction house that only lost a portion of roof and the add-on
porches, etc.

It appears that the 4-sided roof shape of the small houses and their
small size was pretty effective in minimizing the damaging forces while
the brick walls were simply so stout as to keep walls intact even though
damage was extensive enough it was razed. The typical ranch-style was
simply flattened to the slab almost universally w/ only an occasional
exterior wall or tow here or there or the interior walls in some small
rooms/halls such as closets and/or bathrooms that had some initial
protection.

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