This is a classic immature Tundra head. At this time in February, you would expect more black on the bill of a Trumpeter. A Trumpeter would appear to have a black bill with some pink in the center where this bird appears to have a pink bill with black at both ends.
The rounded head shape just above the mandible, the pinched in feathering at the eye plus the curved line of the feathering along the lower mandible all are good for Tundra. Also the bill on this bird seems to be just stuck on a large head where on Trumpeter the bill almost appears to eat the head. Caution there again as the swan bills reach full size the first winter where the bird's bodies lag only reaching full size in summer.
The ratio of the bill length to the distance from the eye to the nape is near perfect on this bird for Tundra 1 to 3/4 and far from the usual 1 to 1/2 of Trumpeters.