I lived in Denver for a few years and it’s true, the dry air cold is much less debilitating than the humid cold in Florida, for example. In the 20s here now in west central Florida.
I see that it's going to be 20* down near Brownsville, Tex. They will lose their citrus too. My daughter brought a large bag of grapefruit when she came for Christmas.
The nurseries are going to make a killing come the spring, lol, all the garden plants are dead.