Heavyweight Layering…

I’ve got a trip to Jay Peak coming up and the last few years it was blizzard-like conditions with the highs only around 10 degrees. I have some Heavy baselayer pants that button into my Special Blend Toofers but they’re more like xxl sweat pants than a base layer. So does anyone have any suggestions for a heavyweight baselayer pant that will keep me super warm but isnt very bulky