4.2.10 More about the precipitation types
Click on each type of precipitation to learn more about it.

Freezing rain accumulates as a very dense, hard layer of ice on top of the snowpack.

Graupel acts as a very dense, heavy layer of particles, which can compact the top of the old snow. When graupel is buried, it is a weakly bonded layer.

Freezing drizzle accumulates as an ultra-thin, very dense, hard layer of ice on top of the snowpack.

Sleet accumulates as a dense layer on the top of the snowpack and compacts the top of the old snow layer.

Raindrops percolate into the top few cm of the snowpack, creating a wet snow layer. The mixture will eventually freeze when temperatures fall. When crusting occurs, the associated heat release caused by the freezing produces a temperature gradient in the snowpack and facets grow on the snow crystals just below the crust, forming flat edges. If snow falls after that point, we'll have a buried layer of faceted crystals next to a hard ice layer, which could lead to cracking and collapsing in the new snow layer.