There were strong winter storms in the winter of 1863-1864. Like many cold blasts in Texas, it was warm and got cold suddenly.
The Winter Storm of 1863 and 1864 (February 2013)
The Winter Storm of 1863 and 1864 -Part 2 (March 2013)
It was cold for 21 days, but we do not have temperature records of this cold blast. This was a severe freezing rain and ice storm. It was a prolonged event with heavy rain.