Julie writes:

I am leaning toward squirrel after poking around on The Internets. ;) For the first 45 minutes or so, I was thinking those three "prongs" were toes. At approx 8 inches, this does lend itself toward "immature Yeti!" thoughts.

But perhaps not.

Running through a mental checklist of "mammals known to frequent or reside in The Celery Farm", I did lots of google searches. What would have a 3- to 4-foot stride? A person? (Yes, I even looked for photos of Vibram Five-finger shoe tracks in the snow...) A deer? A bear? All not good matches.

I liked the "bounding theory", and was looking for photos of squirrels, eastern cottontails, mink, raccoons, skunk (though interestingly I don't think I've ever actually seen a skunk at the CF)...

Squirrels started to look interesting especially because of their abundance. But a lot wasn't matching up because many of the photos of tracks in the snow that I could find online are of distinct feet and toes. Of course, looking at your close-up of a single imprint seemed to suggest there were multiple feet in there in the deepest section....

I did a Facebook search to see if there was a group for IDing animal prints. There is! https://www.facebook.com/groups/271764596196849/

I perused some recent ID requests, and found this: https://www.facebook.com/groups/271764596196849/permalink/1113471322026168/

It has the three prongs, and so I scanned the comments. There is some dispute, but squirrel did pop up in the suggestions (as well as rabbit and weasel...) with mention of red squirrel and flying squirrel. (The original poster is in British Columbia.) Red squirrel sure seems right out, but I wondered about flying squirrel... so did some more google searches. (Mostly because a friend in Wayne currently has flying squirrels squatting in her house!!) Also, one of the comments on that post mentioned that you can see a central drag mark in squirrels who are bounding in deep snow. I didn't understand this though....

Eventually, I stumbled on this page: https://natureguelphtracking.wordpress.com/mammals/rodents/squirrels/red-squirrel/

If you scroll down, there is a photo of a red squirrel track with a paragraph describing the snow spray and determining the direction the animal was bounding in. I stared and stared and they described the animal as going in the OPPOSITE direction that I would have guessed. And then I finally realised what this is all getting at. The center "prong" isn't a toe. None of the three prongs are.

I believe the deepest part of the imprint is where all 4 feet land in a cluster. The three prongs are the drag of the hind legs, with the tail as the center prong. In your uppermost photo, this would suggest the "squirrel" is bounding to the left.

Additional clues that make me think squirrel are

1. The distance between the prints. One site I looked at suggested grey squirrels average between 1 and 3 feet in a bound.

2. Squirrels typically bound to and from trees. In your photo with multiple prints, it looks as if the animal could be coming from the tree in the background.
I could of course be wrong. Perhaps you should set up a motion-sensitive camera tonight with night vision. Guard against immature Yeti just in case.

At any rate, thanks for a nice hour-long distraction from my raging migraine. :)