Sky, Sky, Sky, so young and so suicidal....
First of all, Grizzlies and brown bears are the same. There is a brown bear population on Kodiak Island which is sometimes considered its own subspecies, as they are are extremely huge due to ideal natural conditions there.
The smaller bears in North America would be the black bears - those are the ones where you
could have a chance to fight and/or flight. I have seen signs in state parks inhibited by both which differentiate between what to do when attacked by either of them. Though it's not always easy for a layman to tell the difference between them, especially under pressure, the color of the fur is no clear indication, as it greatly varies.
The standard recommendation to get on the ground and lay on your stomach when attacked is for the reason to protect your inner organs - usually you should also put your hands around yopur neck to protect it.
You can't outrun a bear, you are the worse climber and the worse fighter.
The chaces are great that you will never see a bear, as usually they smell you before you have a chance to see them. You are in their living room, and usually they want to know what's going on and usually avoid humans - not their prey scheme. What makes a meeting between Mr Bear and Mr Human dangerous is when the bear gets either surprised by your presence or when it's a bear that relates humans and food - the latter would be the so called problem bears, usually bears who lost their shyness against humans, could be bears who were fed by them, or bears who plundered from human setlements. I had a co-worker from Ontario, who told me the best place to watch bears in his hometown was the dump
.
So avoiding bears by making sounds is the most recommended solution - the locals in Alaska tell that the bears over there love to hear poems by Lord Byron, in abundance of wisdom about those, I noticed that German Schlager also works
Trying to intimidate a bear is a bad idea - this is his game, and that's where he is good at. For example, if he stands on two legs can be a sign of this. Another intimidation method would be a charge at you wheree he stops some meters in front of you. That's why it would be terrible to try to yell at him or throw rocks in this moment. What makes the meeting between a human and a bear often dangerous is that these creatures have only limited body language. You can't really tell anything from his face, other indicators can have different meanings, so it's nearly impossible to tell what he wants from this.
So the best way is to slowly retreat, out of his path, out of the comfort zone of the bear. Don't turen you back on him (prey) don't stare into his eyes (danger). You can speak silently to him.
For worst case scenarios you can carry bear spray, it is a pepper spray in a huge-ass container. Don't know if it's stronger than normal one (I doubt it), but the portion size is the right one for a bear. In Germany, the correcponding size would be the 0.5 - 2l "family-size" containers which you can buy here.
Oh, and I love those big teddies, that's why I wrote so much about it, they are amazing creatures, though I would never let my guard down when I see them.