Considering we get an average of 80+" of rain each year, and
"winter" usually lasts from Oct. to April, having god waders is
an absolute must if you're going to be doing much outside, and
especially in/around the water. Glacial runoff is some serious cold
water...even in the summer.
Here's my "first line" of cold defense:
Amazon.com: LaCrosse Men's Brush Tuff Extreme Max-4 1600G Wader Boots: Sports & Outdoors
LaCrosse waders are about as tough as they come. I've had my current pair
handle everything from nasty brush to devil's club, and they still look like new.
Your biggest danger in waders (other than falling in) is from the sharp-ended
sticks that beaver have chewed.
I usually wear a pair of light sweats underneath, but if it's super cold
(as in -0) you can wear poly-pro's underneath, BUT, you need to be
careful about sweating or the Hypothermia Monster will rear it's ugly
head and your day may become miserable.
Lots of good gauntlet gloves on the market, so the key is a dry, warm
body and dry, warm hands. Don't bulk yourself up so much that it
impedes your ability to easily move around, as falling in a freezing
creek with all that gear on ....well, it'd be less than pleasant.