"The Leap" is told retrospectively. The narrator recalls the three events that made her life possible. "I owe her my existence three times." The narrator owes her existence to her mother. The reader gets the impression that her mother is responsible for her being alive. These three events contribute to the rising action.
The first event is her mother saving herself. Lightning strikes during the acrobatic performance. Her mother's first husband is killed; the mother is able to save herself, and the first daughter dies in the hospital.
The second event is the union of her mother and father: made possible by the lightning strike and the fall because they meet in the hospital. So, the first two events are what make the narrator's life possible: her mother stays alive and as a result of the accident, she meets the man who will become the narrator's father.
The reader is now left to speculate what the third event might be. It could simply be her birth itself. But it turns out to be something more dramatic. Note that the narrator does begin the story by illustrating her mother's athletic ability:
She has never upset an object or as much as brushed a magazine onto the floor. She has never lost her balance or bumped into a closet door left carelessly open.
This is just a hint but it does add to the rising action as the narrator begins to the describe her mother's action during the fire: the third event. The two events with the most action that lead to the climax (saving her daughter/narrator from the fire) would be the initial fall and the final leap: the leaps that connect events in life. In the first, the mother saves herself which enables her, years later, to give birth and then save her daughter. There is a poetic connection between the two events. Lightning was the cause of the first fall. And when the narrator is saved in the end, her mother's heartbeat sounds like "thunder, long as the roll of the drums." The drum roll is what one would hear prior to a dramatic trapeze act. The trapeze act/accident foreshadows the "leap" in the end. The rising action is illustrated in how the three events lead/leap to another.