Thanks all. The light fall off in this one is more a function of my position to the sun when this was taken. I used a 2 stop ND filter to give me some polarization, a regular polarizer would have given me some seriously uneven skies. I like the effect personally, adds a little character to the image.
The weather was bone-chilling-cold on Saturday, temps were in the 20-30's up high in the passes, and in the 40's on the valley floor. But there was a fierce wind that made it feel much cooler than that. Sunday was nicer, similar temps, but the wind was non existent.
Thanks for looking!