A burst is a sudden flurry of activity. Bursts of energy are helpful in shoveling heavy snow, but it's better if you work steadily instead of shoveling fast and stopping.
As a verb, burst is your go-to action word to describe something sudden and energetic happening. It usually means, "to explode outward, with noise" like if you burst into song in the middle of study hall, startling everyone. It also means, “to split open in a violent way due to internal pressure” like an overfilled water balloon. It comes from the Old English word berstan, meaning "break suddenly."