2.2.10 Precipitation types
Various types of precipitation impact snowpack: dry snow, wet snow, graupel, sleet (also called ice pellets), freezing rain, rain, freezing drizzle, and drizzle.
What impact does each precipitation type have on the density and depth of snowpack? Assume that the snowpack is fresh and relatively dense. Select the correct answers in the listboxes for each precipitation type, then click Done for the feedback.
Dry snow
Dry, low-density snow decreases the density or SWE of a relatively dense pack. It also increases the depth of the pack.
Wet snow
Wet snow generally increases both snowpack density and depth. But if a thin layer of wet snow falls on a thin layer of dry snow, the depth could actually decrease due to compaction.
Graupel
Graupel is high-density frozen precipitation that typically increases snowpack density and depth.
Sleet (ice pellets)
The high density of sleet causes the underlying snowpack to compact, which decreases its overall depth. As the sleet layer accumulates, it increases the density of the snowpack.
Freezing rain
Freezing rain freezes upon contact with the snowpack, forming a thin layer of dense, hard ice on top. It typically decreases snowpack depth as its weight causes the underlying snowpack to settle. Note that freezing drizzle has a similar, although less intense, impact as freezing rain.
Rain
Rain leads to melting and refreezing in the top of the snowpack, which increases the density of the pack. Rain also decreases snowpack depth. Note that drizzle has a similar, although less intense, impact as rain.