snowblower dies under load
It sounds as if it's running too lean. In cold snowy weather, air is much denser and it's laden with moisture. Moisture slows down combustion within a cylinder and a wee bit of water vapor contributes to smoother ignition and more complete combustion. But, more fuel is therefore necessary to mate with the additional volume of air and the presence of moisture. As already mentioned, the choke may be stuck or inoperative (too much air, not enough fuel) or not enough gasoline is physically entering through the carburetor. Clogged fuel inlet filter if it has one? Gungy or kinked fuel line? Dirty tank?