This is the 17317th most frequent Russian word.
сыпать
To pour or sprinkle (granular substances).
In this sentence, 'сыпать' is used to describe the action of pouring or sprinkling a loose substance (sand).
Маленький мальчик любит сыпать песок на пол.
The little boy likes to pour sand on the floor.
Here, 'сыпать' illustrates the act of something (like snow) falling loosely and freely from above.
Рано утром снег начал сыпать из облаков.
Early in the morning, snow began to fall from the clouds.
In this example, 'сыпать' is used to describe the action of adding sugar, a granular substance, into a liquid.