In the story "Snow," Yolanda most likely shouts "Bomb! Bomb!" when she sees "dots in the air" because she

She confused the snow falling from the sky with missiles (bombs falling from the sky). When Yolanda first came to the school she realized that everybody was so nervous about the missile crisis with cube, and after her teacher Sister Soe explained her and the other girls of the class about the situation, one of the first words that she learned to describe the situation was bomb.