Precipitation Classification
Precipitation is classified by its “state” when it reaches Earth’s surface. Use the books at
your station to complete the chart. Read for Detail to gather information and then
“bullet” your information on the chart.
Weather and Climate by Prentice Hall – pages 62 + 63
Weather and Climate by Holt- pages 42 + 43
Name
Rain
Describe this type of
precipitation:
 Most common form of
precipitation
 Liquid water
 Formed when
temperature is above 32o
F
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Snow
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How does it form? What conditions are
necessary? (details needed!)
 Air cools and becomes saturated
 Air reaches its Dew Point which will be
above 32o F
 Water vapor condenses into a water
molecule that attaches to a solid
 When water droplet becomes about
100 times its original size, gravity pulls
it to Earth’s surface
Most common form of
solid precipitation
Forms when temperature
is below 32oF so that
water vapor condenses as
a solid
Can be individual ice
crystals or many
combined=snowflake


Freezing rain





Sleet




Hail
Forms as solid
precipitation
Falling chunks of ice



Air cools and becomes saturated
Air reaches its Dew Point which will be
below 32o F
Water vapor condenses directly into a
solid ice crystal molecule that attaches
to a solid
When ice crystal becomes about 100
times its original size, gravity pulls it to
Earth’s surface
Air cools and becomes saturated
Air reaches its Dew Point which will be
above 32o F
Water vapor condenses directly into a
water molecule that attaches to a solid
When droplet becomes about 100
times its original size, gravity pulls it to
Earth’s surface where it falls through a
layer of air that is below 32oF
Water droplet freezes producing falling
ice crystals
Forms when updrafts of wind carry
water droplets higher up in altitude
where they freeze into an ice crystals
Ice crystals fall back through cloud and
gather more water and once again get
caught in updraft where they bounce
back up and refreeze – each time this
happens the ice chunks get bigger
Eventually ice chunks fall to Earth