Hi Cori. Welcome. You said the lake has risen more then what snowmelt can account for. Can you see all the way around the lake? If so can you tell if the rise is equal around the lake, or appears to be more on one side or the other? This is how they learned that Yellowstone was rising. The water in the lake went down on one side an up on the other. It’s sort of like a crude tiltmeter. You have two containers of equal amounts of water in them with a tube connecting the two. When one container starts having more water in it then the other this would be an indication of tilt. A lake can do the same thing.

It could also be that the bottom of the lake is rising. If you know how deep the lake is you might be able make a measurement of some sort. Take Care…Don in creepy town