PrecipitationPrecipitation

Another process brought to you by Another process brought to you by the water cyclethe water cycle

The Four Types of The Four Types of PrecipitationPrecipitation

Rain (Freezing Rain)Rain (Freezing Rain)SleetSleetSnowSnowHailHail

RainRain

Can start as liquid water or ice. Ice melts Can start as liquid water or ice. Ice melts as it falls, turning into rain.as it falls, turning into rain.

Hits the ground as liquid water.Hits the ground as liquid water. Rain drops start as a round drop. As it Rain drops start as a round drop. As it

falls it becomes more like a hamburger falls it becomes more like a hamburger bun, flattening out as it falls. bun, flattening out as it falls.

A raindrop can break into two drops as it A raindrop can break into two drops as it spreads out.spreads out.

RainRain

SnowSnow Snow is formed when water vapor turns directly Snow is formed when water vapor turns directly

into ice without ever passing through a liquid into ice without ever passing through a liquid state. This happens as water condenses around state. This happens as water condenses around an ice crystal. an ice crystal.

Snow can be ice pellets or snow flakes. As snow Snow can be ice pellets or snow flakes. As snow falls to the ground, it often melts on the warm falls to the ground, it often melts on the warm surface of the Earth. If the surface of the Earth is surface of the Earth. If the surface of the Earth is chilled sufficiently it begins to pile up creating chilled sufficiently it begins to pile up creating snow drifts. In some locations, such as snow drifts. In some locations, such as mountains, these snow drifts can reach several mountains, these snow drifts can reach several feet in depth.feet in depth.

SnowSnow

SleetSleet

Sleet refers to a mixture of snow and rain, Sleet refers to a mixture of snow and rain, as well as raindrops that freeze on their as well as raindrops that freeze on their way down. way down.

Sleet, unlike snow, is when raindrops pass Sleet, unlike snow, is when raindrops pass through a liquid form before freezing. The through a liquid form before freezing. The result is that they are not light and fluffy.result is that they are not light and fluffy.

Sleet bounces when it hits the ground.Sleet bounces when it hits the ground.

SleetSleet

Freezing RainFreezing Rain

Freezing rain is sometimes called glaze.Freezing rain is sometimes called glaze. Freezing rain happens when water Freezing rain happens when water

droplets become super-chilled. They do droplets become super-chilled. They do not freeze in air, but rather freeze the not freeze in air, but rather freeze the instant they land on an object such as a instant they land on an object such as a road, or car. The result can make roads road, or car. The result can make roads very slippery, and can cause car doors to very slippery, and can cause car doors to become frozen shut.become frozen shut.

Freezing Rain / Freezing Rain / GlazeGlaze

HailHail Hail is formed as nearly round balls of ice and snow.Hail is formed as nearly round balls of ice and snow. Hail is formed, deep within cumulonimbus clouds.Hail is formed, deep within cumulonimbus clouds. There ice crystals form and begin to fall towards the Earth’s There ice crystals form and begin to fall towards the Earth’s

surface. As this happens, wind gusts pick up the ice crystals surface. As this happens, wind gusts pick up the ice crystals pushing them back up high into the clouds. As they begin to pushing them back up high into the clouds. As they begin to again fall down, they grow in size. Again, a wind gust might again fall down, they grow in size. Again, a wind gust might catch the growing hail stone pushing it back up high into the catch the growing hail stone pushing it back up high into the cloud. This may be repeated several more times, until the hail cloud. This may be repeated several more times, until the hail stone becomes too heavy for the wind to carry, causing it to stone becomes too heavy for the wind to carry, causing it to finally fall.finally fall.

True hailstones occur only at the beginning of thunderstorms True hailstones occur only at the beginning of thunderstorms and never when the ground temperature is below freezing. and never when the ground temperature is below freezing.

Hailstones range in diameter from 2 mm to 13 cm Hailstones range in diameter from 2 mm to 13 cm Larger hail can be very destructive. Larger hail can be very destructive. Often several hailstones freeze together into a large, Often several hailstones freeze together into a large,

shapeless, heavy mass of ice and snow.shapeless, heavy mass of ice and snow.

HailHailVideo of hail formingVideo of hail forming

ResourcesResources

http://commons.wikimedia.orghttp://commons.wikimedia.org http://www.geography.hunter.cuny.edu/http://www.geography.hunter.cuny.edu/

~tbw/wc.notes/5.cond.precip/~tbw/wc.notes/5.cond.precip/sleet_formation.htmsleet_formation.htm

www.unitedstreaming.comwww.unitedstreaming.com http://www.kidsgeo.com/geography-for-http://www.kidsgeo.com/geography-for-

kids/0100-atmospheric-moisture.php kids/0100-atmospheric-moisture.php