What sledgehammer force has split apart this boulder?
An avalanche? Lightning bolt? Tornado?
It was actually a force greater than all three – time.
The slow crawl and subtle components of time have the ability to
break down all forms of matter as well as heal all wounds.
m1nute 
Makes me wonder if the crack is a wound or a creation.
An artistic assault?
It’s the ice. The power/pressure of freezing water is quite amazing, repetitive, relentless yet so subtle and unseen.