GG, If your children ask about their father, just say "he was unable to make it, but he loves you very much". Keep it very simple.
I'm glad you and your sister had a great time last evening....baking, watching a movie. Those are the memories that you will hold near and dear in the years to come. More snow? Hopefully, the storm will move out of your region in the next day or so...just think....a white Christmas and Santa can come in his sleigh!
As your MIA h, my xh hasn't been to visit his family on Christmas in a very long time. He did visit an uncle two years ago w/his brother, but didn't take nor mention the HO he had married. All of his cards are signed by him and only him. The HO is nonexistent w/the family. They do withdraw from the family for periods of time and it looks like your h is having difficulty w/the family scenario at Christmas. Just let him be and go on w/your own family "show". It's his loss, not yours.
If you go out, drive safely.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.