Why don’t you PM the info to @Overo Mare and let her take care of it? I would have just called the police or 911 by now, and apologized that no other agency has picked up but you need to report a dog in danger. I’ve never heard of a police station or 911 that didn’t answer.
You could, and just explain you aren’t 100% sure it’s an emergency but the dog is emaciated and out in the cold, and you tried calling animal control but weren’t sure he would make it another night.