Precipitation
ANY form of water that falls from the sky
Not all clouds from precipitation!
Formation: ( must grow heavy enough to fall through the air)
Colliding and combining with other droplets= moves faster as it gets bigger= collects more drops heavy and
fall to earth
Types of Precipitation:
-Rain- most common. Rain= drops bigger than 0.5mm (anything smaller is called drizzle- even small is called mist) Stratus
clouds create drizzle and mist
-Sleet- rain drops freeze as they fall through air that is below freezing. Sleet is smaller than 5mm in diameter
-Freezing Rain- rain falls through cold air and DOES NOT freeze- hits a cold surface and then freezes
(can cause lots of damage- dangerous roads, power outages etc)
-Snow- water vapor in the cloud is converted directly into ice crystals. None have the same
shape but all have a 6 fold symmetry (some times hard to see because they clump together )
-Hail- ice pellets formed in clouds, with a diameter larger than 5mm. Only forms in cumulonimbus
clouds
Modifying Precipitation- Cloud Seeding in times of drought- has not been
effective in forming precipitation
Measuring Precipitation
Snow – Depth of snow measured in feet or meters OR measure the amount
of melted snow (light, fluffy snow contains less water)
Rain– Rain Gauge- to increase the accuracy of the rain gauge a funnel is often
place at the top. This increases the area that the rain is collected= more rain
is easier to measure