Dear Sue, My heart goes out to you, there are no words but we are praying for a safe return of your little guy. Contact the local skidoo club and the local hunter's club and ask them to be on the lookout right through to spring for him. Any news is better than no news.
A neighbour lost a Standard Dachsund one time and I spotted her in a cornfield, despite being a family show dog she had become "wild" very quickly and they had to set a humane trap for her. Once back to the kennel she unwound quickly and became a pet again. When dogs are lost the flight instinct takes over very quickly and you might find you need to set sheltered traps with some of your clothing and food in it. All the best. Rose