Not in Alaska but last spring I drilled through 64" of clear black ice in Yellowknife, NWT.
I use a 3HP 10 1/4" Strikemaster Cobra and run Opti2 full synthetic oil. I also have to clear the chips especially when it's that thick.
I'm good for about 2 feet without clearing the chips. I only made the mistake of not clearing once, took 20 minutes to free the auger.
Won't do that again.
We are currently at 3 1/2 to 4 feet of ice this year.