As Providence Farm mentioned, Alaska is always looking for a way to kill you.
I remember hiking in to a moose kill one morning with the intention of putting up a tree stand to hunt grizzly. It was nine or ten in the morning and the thought of a bear being on the kill that time of day never entered my mind. I was about seventy yards out when I glanced at the kill site to see a very nice grizzly stand on its hind legs looking right at me. I still had the backpack with the tree stand on my back but I threw the rifle to my shoulder and got off a shot. The bear ran into some spruce growth directly behind the moose remains and it went dead silent. I wasn't sure if I had hit the bear or not. I dropped my pack and eased my way in. I'd taken to hunting solo so I didn't have anyone to bail me out if things went bad. To say I was on edge would be an understatement. I couldn't find any evidence that I hit the bear.
Here's a couple of bear from that area. One in the fall on berries and one in denning country in the spring. The bear on the lake knew I was there but didn't know what I was. It saw me and was quartering downwind to pick up my scent, eyes on me every step of the way. You can see from the pic there's no cover. I shot it at seventy or eighty yards. A seventeen year old male with every canine broken off and a cavity in every tooth.