Husky’s Eyes Change Colors

My son recently purchased a Husky. She is about 14 weeks old. When she plays with our dog and seems to get angry, her blue eyes instantly turn red. They seem to be like rivers of red overcoming the blue. This last only a second or two. What causes this? It is both so interesting and scary at the same time. It is like a rush of redness.

Gordon, with all these knowledgeable Husky Dogsters out here, I bet at least one of them knows the answer!