When Holden and other boys come out of the dining room, they see the pristine snow which has fallen.

. . . we all started throwing snowballs and horsing around all over the place. It was very childish, but everybody was really enjoying themselves. (Chapter 5)

Holden decides to join a friend named Mal Brossard on a trip into Hagerstown to have a hamburger and watch a movie. Because he has asked Mal if Ackley can come along, he must wait while Ackley gets ready. As he waits, Holden opens the window and packs a snowball. This time, however, Holden does not throw his snowball because when he gets ready to throw it, he notices how each target he selects looks "so nice and white" that he does not want to change anything by tossing a snowball on it.

Holden refrains from throwing the snowball out the window because it looks perfect; also, the parked car and fire hydrant seem pristine, and he does not wish to mar them by striking them with the snowball. Holden's name itself suggests his problem: He wants to "hold on" to things and people in their pristine states. This attitude extends to his desire to catch children and prevent their falling into the corrupt adult world and why he tells his sister he wants to be "a catcher in the rye," holding back innocent children.    

In Chapter 5, Holden opens his window and makes a snowball with the intent of throwing it at something. He changes his mind because he takes notice of the pristine snow that has fallen:
"I didn't throw it at anything, though. I started to throw it. At a car that was parked across the street. But I changed my mind. The car looked so nice and white. Then I started to throw it at a hydrant, but that looked too nice and white, too. Finally I didn't throw it at anything." (Pg. 36)
On one level, this shows Holden's respect for nature, which symbolizes the respect he desires from the world around him.
On another level, this scene is a motif that emphasizes the theme of Holden's difficulty in grasping the concept change. Like the ducks on the pond, winter is fleeting. The ducks and the snow prove to Holden that change is necessary--it's inevitable.