Fluted / spiral crape myrtle trunks: do we know what causes this?

Where I live (southern California near Los Angeles) there are tons of crape myrtle trees. Most have straight trunks, but some of the older trees have an amazing fluted spiral trunk. I've only seen this on bigger single-trunked trees, never on younger or multi-trunked crape myrtles. When there are a bunch of crape myrtles lining a single street, they usually all match, either straight or spiral.

All my searching turns up nothing about crape myrtles specifically, but a few web pages (such as here and here) mention this spiral pattern in other trees. They offer some theories about what causes it (wind, or asymmetrical access to nutrients), but there doesn't seem to be much certainty.

We do have winds here in the spring and winter. About once every ten years we'll have a major windstorm that takes trees down. (The last one was January 2025.)

I am wondering if anyone knows any more about this spiral trunk phenomenon, and whether it's reproducible?