When you write a short story, you must draw your reader into the action quickly because your space is limited. The rising action of a story builds interest in the characters, their challenges and the plot itself, and culminates in a climax. Without rising action, your climax won't seem as interesting or exciting, and your story's ending will have less emotional weight.
Rising Action Role
The rising action of a short story moves your story toward the climax. The climax is the moment of ultimate conflict or excitement. For example, if you're writing a love story, it could be the moment at which the characters decide whether to break up or stay together. Rising action sets the stage for this moment by creating problems or situations that are more and more dramatic and add layers of complexity to both the characters and the plot as you head toward that climax.
Rising Action Events
There's no specific event you have to include in rising action. Instead, the rising action should progressively move the story forward. In the introduction, you might give some preliminary information about your characters and their struggles. During the rising action, provide more information about your characters and introduce events that further reveal the characters' personality and struggles. The rising action should become steadily more complex and dramatic as you move toward the climax. Introduce at least one conflict -- even if it's just an internal one -- during the rising action.
Rising action plays a major role in character development. A character introduced as a bookish loner, for example, might begin spending time with a more social crowd during rising action, and might give a public speech during the climax. Characters who aren't further developed during rising action or who don't undergo any changes during the story are flat characters. If your story consists of nothing but flat characters, the rising action might not be sufficiently well-developed.
Rising action ends with the climax, which should bring the conflicts presented in the rising action to a head. After the climax, a reverse of rising action, called falling action, occurs. Falling action ties up loose ends, gives your reader an idea of what will happen to the characters, and leads to the conclusion, at which point the central conflicts are fully resolved and the story ends.