Cold low light non moving subjects

Hi, great to see such active forums!

I am the snow artist and my fans are complaining I havent got any really good high resolution photos of my drawings, and I havent yet found advice specific to my problems of cold.

I photograph my snow drawings and also sunsets from mountain-tops, and I am considering buying a camera with a medium format sensor, focus is approximately infinity, but a zoom lens is useful, you may assume I will be using a tripod.

Many thanks for any advice, I need image quality and reliability in the cold, not interested in burst mode, shooting insects, or other moving objects.

Simon Beck (snow artist)