Steven Rinella is on a show called "Meat Eater" where hunters trek across the pacific northwest on hardcore hunting expeditions. In this episode, they come across a cranky Grizzly Bear with a couple of cubs in tow.
If you ever find yourself in a situation where you're being chased by a Grizzly Bear, try to keep your head. Chances are good that the bear is doing a "False charge." This is how bears scare up their prey. By running away, you show them that you are a meal.
Try to stay down wind and spot nearby cubs. Let the bears know you're there by making noise.
Continue making a lot of noise if the bear gets closer. If you've got bear spray, or a weapon, get it ready.
If the bear continues to come, stand your ground. Shoot in front of the bear to scare it away.
The bear is trying to see if you are prey. If you don't panic, there is a very good chance she will turn around and run away.