Plants/trees are not humans, they are not subject to wind chill with the exception of inducing desication. If you got bark, it aint a problem.
Living in Texas for many years and watching typical Texas temp swings from mid 70's one day to sub freezing the next morning I've noticed it's a sudden temp swing that nails sensitive trees and plants and very much drives cold hardiness. You can throw that book "this tree is cold hardy to 28F" stuff out the door. If your trees have been subjected to near freezing temps before the big one hits they are in much better shape. I think the effect is one of sap and sugars translocation.
What's happening now is very wonky. I belong to a very active Facebook gardening group called Central Texas Backyard Gardeners and folks are seeing all kinds of strange stuff like a flush of water shoots low on trees and shrubs, etc. and of course lots of dead material. I have a few large Monterrey oak trees that normally would be pushing spring foliage in February. Most are still dormant or barely pushing - mid April!
The Uri Winter Storm we got which bopped right into N. Mexico was unprecedented. That super cold cyclonic system can and did move over mountains just as easy as plains.
What's crazy is Reed is pushing shoots from just above the graft to to about 8' up. The 3 trunks are those I selected that pushed after the 18F low in 2018.
12' tree
Cropped shot of some of the shoots, some already 10" long