There aren't many metaphors in this story, though there are some examples of personification. Personification is the literary device with which writers attribute human characteristics to nonhuman things—so in some ways, we might consider it a kind of metaphor. For example, consider this passage:

Blue creeping up fissures and cracks from depths of several hundred feet; blue working its way up through the gleaming ribs of Ann's buried dogs....

In the above quote, "blue" is a reference to the fields of snow that have turned to vast sheets of glazed ice. The ice shimmers blue in the moonlight. Personification gives "blue" the human quality of intention, comparing it in a way to a living thing, one that creeps up fissures in the earth and envelops the dogs in frosty layers of freezing cold.

Another example of a metaphor from the story is the following:

The quail would fly off with great haste, a dark feathered buzz bomb disappearing quickly into the teeth of the cold....

Here, the "cold" is personified, and the extreme weather Ann and Gray Owl encounter on their journey is given "teeth." We also have the strongest example of a true metaphor here as a bird is compared to a "buzz bomb."