DS took three pairs of those ski mittens (required) to Okpik (winter snow camping) to build Quinzhee (sort of igloo to sleep in.)
While we are at mountaineering/outdooring, Merino Wool Socks!
Not heavy but light ones.
http://www.jaxmercantile.com/products/smartwool-womens-hiking-light-crew-socks.html
http://www.jaxmercantile.com/products/smartwool-womens-mini-fairisle-sock.html