I have to make a confession: I don't really know what "fierce" (as the word is supposedly used in the modeling world) really means. Oh sure, I've seen a little Next Top Model, but I must confess that I can't always see a whole lot of difference between the "good" photos and the "bad". Same goes for the reality shows about singing, dancing and what-have-you. (Those rare times when I actually watch a little of the show,) I have a hard time guessing which performances the judges are going to be wowed by and which they'll dismiss as nothing special.
Still, I'm going to go out on a limb and say that this strikes me as a knit/crochet model's version of a moderately "fierce" expression:
. . . And goodness knows she needs it, when they put her in such a ridiculous-looking hat.