The first thing that is noticeable about the poem is that it is actually just one long, complex sentence. There is no rhyme, and there is no particular meter. Each foot varies: the poem becomes a combination of iambs ("the frost," "and not," "the sound," "that is"), trochees ("winter," "glitter,"), anapests ("to regard," "to behold," "of the land"), dactyls ("junipers"), and others that are not of those kind ("that is blowing" - unstressed, unstressed, stressed, unstressed). Also, each line has either 3 or 4 feet, and the variation per stanza is not even regular.
This very structure actualizes the opening line of the poem, which calls for "one [to] have the mind of winter." The title suggests that this is actually the mind of "the snow man." By reading and reciting the poem, one gets the sense of assuming another mind whose thoughts are the contained in the rest of the poem. The poem's structure allows this by imitating the normal way of thought, which normally does not come in complete sentences, nor in rhymes or regular rhythm. Instead, mind activity is usually a "stream of consciousness," a continuous and an uninterrupted flow of thought. Thus, the structure is appropriate for the poem, and its theme - that of leaving behind one's own mind and assuming another's - is revealed.
One question that may arise with this function of the structure is this: if the poem really was meant to imitate the mind's flow of thought, then why did the poet not write the poem in just one long line instead of dividing it into five tercets of three lines each? The answer to this is another function of the structure, which is creating the poem's mood and tone. The dramatic situation is set on a cold and quiet winter day, with very little