Gizmo is gone

We don't know what happened to him. I saw him early in the day on Friday and then later started looking for him when I got ready to give him a bath later. Well, he was nowhere to be found. It's not unusual for him to get out of the yard, so I was not overly concerned until several hours later when it got really cold as the sun went down and he still wasn't home. He didn't normally go far.... we think maybe he got out and had a seizure (he has been having them for years) and then maybe froze. I miss Gizzy as we have had him for over 10 years.