Foreshadowing is a literary device used to plant hints about events that will occur later in the plot. There are a number of excellent examples of foreshadowing in this story. The first comes at the end of the second paragraph, when the narrator tells us about how she imagines hearing a fire, that we later find out is a major part of her story:
I hear the crackle, catch a whiff of smoke from the stove downstairs, and suddenly the room goes dark, the stitches burn beneath my fingers, and I am sewing with a needle of hot silver, a thread of fire.
Such events clearly hint at a future revelation in the story of the narrator and her mother. Equally, the description of her agility and "catlike precision" and her skill also foreshadow the rescue of her daughter that she enacts during the fire. Note how the jump is described before the narrator's mother makes the leap:
From below, it looked as though even a squirrel would have had trouble jumping from the tree onto the house, for the breadth of that small branch was no bigger than my mother's wrist.
Of course, it is only someone with the skill and precision of the narrator's mother who is actually able to perform the leap, and what is more, do it in such a "matter-of-fact" manner.