Question about homeowner's liability?

What’s actually happened is that a 25 foot tall ice stalagmite fell intact off my neighbor’s house and struck mine at 5:30am today. It landed directly between two windows, and other than some minor cosmetic damage to the house, nothing is broken.

What I’m curious about is the hypothetical situation where the had hit a window and broke it, possibly injuring the people inside, and how the legal theory would work out?

The house next door is a rental property with a private landlord (e.g., no management company), but would the landlord be negligent in not cleaning the ice off his house (as I have done, and as the other rental property on the other side did)—is this a “standard of care” issue?