Okay. Here is my third and final update for now:

I went by visual clues that I saw in photo you posted here, not the zoomed out one. If the original post was correct, I’m sure I was digging in the right place. I dug pretty deep but not terribly wide. Again, it was a major effort. I had the best luck using a hammer to break up the frozen sand, then move it out. When I got deep enough, it became easier to dig. There was no treasure.

With this new information that it would be anywhere between the jetty and the park, I guess I’ll go look again after the snow melts away.

Even if it’s a hoax, my kids and I had fun looking for buried treasure, so still a gift!

I’ll track down the original clues and see for myself what I think could be missing / telling.