This happened in an instant, which is why it's so compelling. Some lumberjacks were about 20-or-so feet away from a tree they were toppling, and when it hits the ground a massive branch pops loose and shoots right at them like a missile.
It clips one guy in the hand, and whoever's filming it loses control of the phone. It's not clear if anyone was seriously hurt.
You can do everything right when it comes to felling a dead tree, but sometimes nature plays funny (and very dangerous) tricks.