PRECIPITATION Chapter 11.3 notes

What is Precipitation? Rain Snow Sleet Hail Freezing Rain Precipitation is the falling of any form of water from the air to Earth’s surface. Examples: Rain Snow Sleet Hail Freezing Rain Condensation Nuclei anything water vapor can condense onto such as dust, smoke, salt, etc.

Types of Precipitation RAIN: (Condensation) Forms when condensed water vapor forms tiny water droplets in clouds. When the droplets get big enough (Coalesce), they fall to the Earth.

Types of Precipitation 2. SNOW (Deposition) Forms when the air temperature is below freezing, water vapor turns directly into a solid. These ice crystals fall to Earth as Snow.

Types of Precipitation 3. SLEET: (Snow-Rain-Freeze) Forms when rain passes through a layer of air which is below freezing. The rain then freezes into ice and falls to the Earth.

Types of Precipitation 4. FREEZING RAIN: (Snow-Rain) Forms when the Earth’s surface is below freezing but the atmosphere is warm. When rain hits the surface, it freezes on contact creating a layer of ice on the ground, trees, cars, power lines, etc.

Types of Precipitation 5. HAIL: (Summer-Time) Forms when a rain drop in a cumulonimbus cloud is blown to the top of the cloud and freezes. This frozen drop then falls down through the cloud where it “grows” by collecting more liquid water. This process continues until the hail stone is too heavy to stay in the cloud and falls to Earth.

Water Processes Solid Water (ice) turns into water vapor (gas) Liquid water turns into a Solid (ice) FREEZING Solid water (ice) turns into a liquid MELTING Liquid water turns into a gas (water vapor) EVAPORATION Water vapor (gas) turns into a liquid CONDENSATION Water vapor (gas) turns into a solid (ice) DEPOSITION Solid Water (ice) turns into water vapor (gas) SUBLIMATION

The Water Cycle The Water Cycle (also known as the hydrologic cycle) is the journey water takes as it circulates from the land to the sky and back again. The Sun evaporates water from the Earth's surface (oceans, lakes, etc.). The water vapor eventually condenses, forming tiny droplets in clouds. When the clouds meet cool air over land, precipitation (rain, sleet, or snow) begins. The water flows downhill as runoff (above ground or underground), eventually returning to the seas where the process begins again.