Just a quick note about winter tracking. I don't track dogs below 20 degrees, because I don't think it's safe. But tracking in snow does help the dog. Even if you're out in the back yard, you will see dogs stick their noses down into footprints and sniff. I love this photo of Tess, Devon's littermate. This was taken on a walk, but she's in classic tracking posture and her nose is right in those footprints!
Another advantage to tracking in snow, is you see what other tracks have been through your own. Ever wonder what you dog looks like when it comes upon a deer trail? Look for deer tracks and put in your track right through them. You can really see your cross tracks and see how the dog works them.
One thing to be cautious of is the salt used on parking lots. It can burn dogs feet, so have the dog wear boots or take a wet wipe and clean the dogs feet as soon as they're in your car.
Don't let a little snow run your goals for spring tracking tests! Layer up and go have some fun!