Staying warm in the bush

I finally dragged my lazy butt out of the house today for a nice hike in the bush. The weather was perfect. It was snowing and mild at about minus 20 ... still cool enough to try out my new Canada Goose parka for about an hour. There was a problem. After about 20 minutes of hard hiking, it was too warm! I was actually sweating.
I had to stop at one point and open the front and cool off. That's not a serious problem. Santa Claus was generous this year but the parka should last a few years longer than most. My first extreme weather parka was a Woods brand... it lasted 17 years. I remember it was so warm I could go ice fishing and lay down on the ice for a snooze and not notice the cold. The Canada Goose cost a few extra bucks, but I think it will keep me toasty warm for a few years.