According to an article on LA CBS Local, the charter bus was making a left turn out of the driveway onto Palos Verdes Drive South when it veered further to the left and went down an embankment, crashing into a fire hydrant and rolling onto Terranea Resort, a luxury oceanfront resort near Catalina Island.
Thankfully, nobody seriously injured, at least according to the article. If people were injured, they would need to speak to a Los Angeles bus accident lawyer to protect their rights.
So far, it sounds like the driver suffered a medical emergency or had a medical condition.
Sometimes when people are injured, insurance companies will point to the medical condition as an excuse. In many cases, this makes them or the company the bus driver worked for liable for the injuries. For example, if a diabetic is driving a bus and has known sudden bouts of hypoglycemia, they may have special rules for operating a commercial vehicle and if those are neglected, this would be negligence.