The release is always inevitable.
The three other sections represent the residing of the storm outside, and the storm inside Calixta.
As Calixta and Alcee finish making love, the rain stops and the sun comes back, showing that everything is back to normal. Although the storm of passion inside her attempted to ruin her marital life, as it passes, life seems to go back to normal. Calixta is happy to see her family, and life is good. Although whether the storm will come is inevitable, the majority of life is storm free. And as the reader can see upon the arrival of her family, and the love letter Alcee writes to his wife, love is what drives people to live, not passion.
This division at the end helps to justify the cliché happy ending by separating itself from the oppression in the first section, and the adultery in the second.
Chopin separated her short story “the Storm” into five sections to represent the stages of the literal storm occurring in the story, and to symbolize the storm of sexual passion inside Calixta which is natural to every women. This division helps the reader to separate the literal storm and the storm of passion