define “cloud” state the 3 types of clouds and their characteristics. state the 3 groups of...

• Define “cloud”

• State the 3 types of clouds and their characteristics.

• State the 3 groups of cloud heights.

• Explain the process of cloud formation.

• State the types of precipitation.

LEARNING OBJECTIVE:We will learn about clouds and their influence on the weather.We will learn about clouds and their influence on the weather.

CloudsClouds• Visible masses of liquid water Visible masses of liquid water

droplets or ice particlesdroplets or ice particles

• Fog – Cloud on the groundFog – Cloud on the ground


Cloud ClassificationCloud ClassificationThree classifications:Three classifications:

StratusStratus

CumulusCumulus

CirrusCirrus

““sheet-like”, flat, layeredsheet-like”, flat, layered

““piled”, puffy, verticalpiled”, puffy, vertical

““curly”, whispy, featherycurly”, whispy, feathery


Cloud HeightsCloud HeightsThree heights:Three heights:

StratoStrato

AltoAlto

CirroCirro

Low clouds (2000 m)Low clouds (2000 m)

Middle clouds (2000 – 6000 m)Middle clouds (2000 – 6000 m)

High clouds (above 6000 m)High clouds (above 6000 m)


Cloud Formation• Clouds form when rising air is cooled below

its dew point

• Tiny particles called condensation nuclei in the air allow a cloud to form


Precipitation

• Rain and snow = most common forms of precipitation

• Drizzle is small raindrops that fall slowly

• It has to be 0 Degrees Celsius in order for it to snow.


Precipitation

• Sleet is a partially frozen mixture of rain and snow that occurs when the temperature is just above freezing

• Freezing Rain is super cooled rain that when it touches an object it freezes.

Precipitation

• Hail is in the form of ice balls, which usually occurs in violent thunderstorms– Hailstones begin as snowflakes that start to

melt and gather more moisture as they fall

PrecipitationPrecipitation


Natural Hazards• Thunderstorms

– Most occur in the summer when the air is warm and moist

– Advancing cold fronts may push the warm air upward, causing the formation of giant cumulus clouds, and heavy precipitation

– Lightning, damaging hail, and tornadoes are possible

• Lightning strikes, flash floods and tornadoes spawned by thunderstorms cause about 100 fatalities per year in the US


Thunderstorms

• Thunderstorms damage• Flash Floods- sudden large movement of water

that can quickly wash away objects.• Winds – very strong winds• Hail – large hailstones can damage property • Lightning- can kill or damage anything it hits

Natural Hazards• Tornadoes

– Most common in the spring and early summer over the central US

– Are usually less than 0.3 miles (0.5 km) in diameter and usually last for 10 min or less

– Winds have been measured by radar in excess of 300 mi/hr


Tornadoes

• Tornadoes form from warm humid air masses that meet cold dense air

• Tornadoes become visible when it lifts up enough dust and debris from the ground.

Natural Hazards• Hurricanes

– Tropical depressions, areas of low pressure that usually develop in the late summer and early autumn in the Atlantic Ocean between South America and Africa

– When winds exceed 74 mi/hr the designation is changed from tropical storm to a hurricane


Tropical Storm FormationTropical Storm Formation


Tropical Storm CategoriesTropical Storm Categories

CategoryWind Speed

(mph)Damage at

LandfallStorm Surge

(feet)

1 74-95 Minimal 4-5

2 96-110 Moderate 6-8

3 111-130 Extensive 9-12

4 131-155 Extreme 13-18

5 Over 155 Catastrophic 19+


define “cloud” state the 3 types of clouds and their characteristics. state the 3 groups of...

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