In the terrain you describe...I certainly would not consider the .44 mag.
"Worst Case" scenario means you would be faced with a chance to get off
(one to none) shots.
A bear charging from 50' (a long way) will likely be on you in about 2 seconds (no kidding). Even if you saw him/her first...and determined yourself to shoot, you would not get off 3-4 shots with ANYTHING (22,38,44,500....you pick). So...forget about controlled/well placed shots.
I believe you are correct to lean towards the most powerful sidearm (shooting the heaviest bullet) that you can.
If you are serious about purchasing a "task specific" weapon then I wouldn't consider anything less than the .454
Also, stay away from ultra short barrels (anything under 4")...as you will give up significant velocity/energy. Remember, you'll probably get off only one shot.
If it were me, (and finances allowed) I would opt for a 5" S&W 460.
They run about $300.00 more than the Alaskan, but would allow you to shoot: 45 long colt (for practice, small game), 454 Casull (Bear, etc), as well as S&W .460 (another level of power).
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Consider the added weight and built in compensator... and you would have a fairly controllable weapon with 460 fodder.
45 LC would be like shooting 38 special, 454 Casull would be much more manageable too.
Heavy bullets designed to penetrate and break bone are what you need. Decide for yourself what you want to launch them out of, but my advice for Grizzly/Brown bear would be to stay away from the .44
Good luck choosing, and post pics when/if you get something.
Flint.