Minimal, Clean, and Unadorned
Mark Twain would love this book. Why? Because there's not a single adverb.
Okay. Actually, there are two: s-l-o-w-l-y, and very. Well…three. "Just" is used, too, as in the stick that was "just right for smacking a snow-covered tree" (19). But that's it. We swear. And that's something.
Keats's writing style is minimal and clean. His sentences are simple, and they say only what they need to say to convey Peter's actions and feelings. While the topic he's writing about is one of great magic and wonder—a snow day!—he keeps the language precise and unassuming. There are no attempts to catch the reader up in Peter's excitement or to make us feel anything beyond whatever natural reactions we may have to the story.
In this way, by keeping the text unadorned with too many adjectives, adverbs, or literary devices Keats allows the reader to enjoy Peter's adventures in the snow as a peaceful observer, a technique that reminds us of the quiet that a blanket of snow can throw over the earth.