The snowstorm on the night of Mrs. Weston's Christmas Eve party in Chapter XIV of Jane Austen's Emma has great significance to events and is pivotal to the direction of the story. Who would think a simple snowstorm and ill judged marriage proposal could have so much impact.
As a result of the snowstorm, Mr. Elton is rejected by Miss Woodhouse and goes to Bath to sulk abd recuperate his shattered ego. There he finds a wife and brings home the resistible Mrs. Elton with all her "resources." Mrs. Elton then triggers some other monumental events with pivotal conflict action that wouldn't have arisen without her, such as the scenic excursion and picnic, the strawberry party and Jane's final decision to take a position as a governess.
Because of the snowstorm, Harriet is heartbroken but also has opportunity to fasten her desires on Mr. Knightley, which awakens Emma's awareness of her true feelings for him and provides the impetus for Harriet to retire to London where she is reunited with Mr. Martin. The turmoil also sends Mr. Knightley to visit his brother in London where the happy family picture of marital bliss causes him to resolve to declare his love to Emma and ask for her love in return.
And Emma...well Emma is granted a few causes for outrage and a chance to transfer Harriet's affections to Frank Churchill (before Harriet falls for Knightley). She then has the splendid opportunity to become jealous when Harriet announces that she spurns Frank and adores Knightley, who then has the chance of giving his blessing to Harriet and Mr. Martin. Whew. What an eventful snowstorm--it unleashed a veritable snowstorm of events.