Keeping your feet warm and dry during winter miles and snowy fat bike adventures is crucial. It's also easy--just slip on something with a neoprene face, fleece lining, fully taped seams, and clearance for lugs. Something like the Louis Garneau Thermax II Shoe Covers. With their combination of insulation and weatherproof protection, the Thermax II booties certainly live up to their name. The only risk of exposure is through the sole of your lugged mountain shoes or the top of the extended ankle cuff. LG can't speak for the former, but a side entry, wrap-around hook-and-loop closure system virtually eliminates the latter.