You certainly have an unusual problem, but the weather has got to be the difference up there, I agree. Replacing the foam grips is possible, hack the old ones off, clean as well as you possibly can with solvent. Then affix new ones.
A guy that makes fishing grips is who you want to seek out. You want a set fishing grip foams made for your REV handles and there's got to be a guy making custom fish poles up in Alaska! The stuff comes in different densities, porous sounds like a bad choice. Try a thinner diameter of foam that is very firm.
Here's a picture of mine (glenn haynes foam) They're red, white & black diagonal foam strips, assembled it's much longer than a regular grip on a REV handle. Since the handles basically "drag on the ground" 'cause they are so long, 17 inches between the two attachment points, (19" grade 5, titanium tubes, 3/8 diameter) A long piece of foam doesn't look unusual. Eventually I'll have to get around to making 'em "no-snag" thru the nail technique.
You could also go the way of the TC Ultra Handles, they are plexi and the winder's built in!
You could wrap your handles with synthetic leather (or some funky hide available no where else?) instead of using foam.
The coolest set of handles I've ever seen are made by Mike Van Meers, Wood layers with a pistol grip that fits your finger outlines, . . .... you can rock 'em on different fingers, so comfortable. I'm still waiting for Burka to have sympathy on me and donate his extended length set
to me in an effort to further my education in quad. Jeff has the only long set I'm aware of, I'm so envious of him!