An iceberg travels across the surface of the ocean and stops over Bikini Bottom, causing it to snow underwater. Everyone is having fun in the snow, and SpongeBob and Patrick decide to have a snowball fight. Meanwhile, Squidward is relaxing at home with a cup of tea. He hears the sounds of SpongeBob and Patrick's fighting and tells them to quiet down. They try to convince him to come out and play with them, both trying to get him on their own side, but Squidward shoots both of them down.
Squidward decides that, as entertainment, he will watch them fight, hoping they will get hurt. SpongeBob and Patrick realize that snowball fights are for children, and they sign a peace treaty. Squidward tries to convince them to continue, but repeatedly gets hit with a snowball by Patrick. He then decides to throw a snowball and misses. SpongeBob and Patrick then proceed to duck behind their fort and mercilessly begin to pelt Squidward with snowballs. A frustrated Squidward then proceeds to throw a snowball and hits SpongeBob right in the face. He then becomes exhilarated and begins relentlessly pelting SpongeBob and Patrick with snowballs. After being hit by a snowball containing his clarinet, SpongeBob and Patrick decide that Squidward is taking the snowball fight far too seriously and sneak off.
When Squidward notices that the snowballs have "stop falling", Squidward becomes paranoid and riled-up and decides to make his fort bigger and eventually builds it to the size of a tower. Squidward continues to throw snowballs as an overhead tree branch keeps dropping snow on his head that he believes are snowballs being thrown by SpongeBob and Patrick. Meanwhile, SpongeBob and Patrick relax in the pineapple watching TV with hot chocolate and popcorn.
The scene where SpongeBob battered Patrick with barrage of snowball rarely shown in Indonesia due to time constraints (Much like other episodes, it also paired with ads during it's airing).
This episode airs a bit in December due to being a snow-themed episode.
This episode probably took place after "Christmas Who?" since SpongeBob wears a santa hat for part of the episode which suggests that he was already familiar with Santa Claus at the time of this episode.
Patrick's alias "Pink Menace" is a reference to the "Red Menace," a nickname for the Soviet Union that was popular during the Cold War.
The Title is a reference to the phrase "snowball effect" which means:
Literally: The effect used in a cartoon when a skier is skiing and trips and falls and makes a snowball that grows bigger and bigger.
Metaphorically: When a situation gets out of hand.
"The Snowball Effect" is also the title of a famous short story by Katherine MacLean.
Netflix mistook the title for, "The Snowball Affect."
When Squidward speaks about his being attacked in the rear, there is already a wall there and all he does is turn around, laugh, and pat the wall. But he is never seen building it.
When Mrs. Puff blows the snow off her boat and onto a nearby fish, the fish pops his head out, and yells "Hey!," although his mouth doesn't move.
When Squidward is demonstrating his fort and how it should be used, and Patrick throws snowballs at him, his arm doesn't move.
When SpongeBob is first seen with his fort, it is circular and shorter than him. But when the camera returns to SpongeBob, his fort has changed shape and is about as tall as him. And when the camera returns to SpongeBob again, his fort returns to how it originally was.
When Squidward drops his snowball after he refuses to be on neither Patrick or SpongeBob's side, the mark that he makes in the snow disappears when the camera pans out.
When the camera shows Patrick laughing after hitting SpongeBob with a snowball, his fort is smooth. Before, it was full of bumps. Also, when Patrick comes upon the barrage of snowballs SpongeBob serves at him, his fort is bumpy again. Also, all the square snowballs he was seen with are gone.
When a closeup of the DNA strand snowball Patrick made is shown, the sky is light blue instead of gray.
When Squidward gets frustrated by Patrick's continuous snowball throwing at him right after he builds his small fort, he attempts to throw back a snowball at Patrick but misses his shot. Instead, the snowball goes inside Squidward's house and puts out his fireplace. This wouldn't have been possible because his house is behind him at the moment he throws the snowball.