6 Precipitation Processes and Types Free Online FlashCards

What is precipitation?

Water, liquid or solid, that falls from the atmosphere and reaches the ground.

How do droplets grow in warm clouds?

In warm clouds, droplets collide and merge until they grow large enough to fall.

How can snow crystals become rain?

Rain can form when snow crystals melt as they fall through warmer air.

What distinguishes drizzle from rain?

Drizzle consists of very small, closely spaced drops, often falling from low clouds.

How does hail grow and fall?

Strong thunderstorm updrafts carry ice particles through supercooled water droplets, which freeze onto them. Hail falls when it becomes too heavy for the updraft to support.

How is precipitation amount usually measured?

It is usually reported as the depth of liquid water accumulated over a stated period. Frozen precipitation can be melted to measure its liquid-water equivalent.

What does snowfall depth measure?

Snowfall depth is the depth of newly fallen snow on a representative, level surface, often measured using a snow board.

How do ice crystals grow in cold clouds?

Ice crystals grow as water vapor deposits on them.

When does falling ice reach the ground as snow?

Snow reaches the ground when its ice crystals do not melt completely on the way down.

How does sleet form?

Snow melts in a warm layer aloft, then refreezes into hard pellets while passing through a sufficiently deep subfreezing layer near the surface.

How does freezing rain form?

Melted drops pass through a shallow layer of subfreezing air and freeze on contact with surfaces.

What is graupel, and how does it form?

Supercooled droplets freeze onto snow crystals, forming soft, opaque pellets that are generally smaller and more fragile than hail.