Where do deleted tracks from Explore go?

I had a bunch of tracks on my Zumo XT. I was going on a big trip and didn't want to look at all those old tracks so I synced them to Explore and removed them from my Zumo, thinking that they would be stored on Explore. When I came back and went to look for the old tracks on Explore, they were all gone. Anyone have any idea where they might be?