I've never seen anyone cleaning them anywhere. Pretty sure the solar farms either have slightly warmed panels that will reduce the friction of any coverage enough to leverage the panel tilt - or since a lot of the installs will follow the sun anyway they probably have a mode of operation to "dump" the panels clean.

I have someone coming out to go over a solar quote I had done, so have some new questions to ask!

The solar panels in my roof shed snow way faster than the shingles do. I suspect it's a combo of the angle plus them being slick glass rather than rough asphalt paper.

Maybe they're warmed too, I've never actually touched them.

If they're still producing any power, they'll have some self heating just through waste.

I'm fairly certain that solar panels catch some power off of infrared and the like, so they should still be getting a little bit warm. Snow is a great insulator, so that heat has nowhere to go but melt base layer of snow off.

After that I imagine it's like a glacier, slipping on a small layer of water