1. Seasons and Weather
Chapter 3:
Section 1

2. A Human Perspective
The smell of thousands of decaying corpses hung in the air in what was once the thriving seaport of Galveston, Texas. The day before, winds estimated at 130 miles per hour roared through the city. A Storm surge of seawater more than 15 feet high pushed a wall of debris across the island of Galveston. Through this turmoil, Isaac Cline’s family huddled in their home. A trolley trestle rammed the house until at last it collapsed, and the waves poured in. Cline survived, but some of his family did not. With a toll of 8,000 human lives, the “Great Galveston Hurricane” would be the deadliest hurricane to hit the United States. The storm date was August 8, 1900.

3. Seasons The seasons are related to the earth’s tilts and revolution.
Some locations receive more direct sun rays because of the earth’s tilt.
Revolution: one complete orbit around the sun. (365 ¼ days)
Rotation: earth makes one rotation every 24 hrs.

4. The causes of the changing season on the earth?
Solstice occur around December 22 & 23 & around June 21 or 22.
Summer, sun hit directly at Tropic of Cancer.
Winter, sun hit directly at the Tropic of Capricorn.
24 hrs. of light or darkness in Arctic Circle or Antarctic Circle.
Equinoxes is Latin for “equal night”
Poles are not pointed toward or away from the sun & both hemispheres receive exactly 12 hrs of sunlight.
Spring, March 21, is called Vernal Equinox. Northern Hemisphere.
Fall, September 21, is called Autumnal Equinox. Northern Hemisphere.

7. Weather Weather and climate are often confused.
Weather is the condition of the atmosphere at a particular location and time.
Climate is the term for weather conditions at a particular location over a long period of time.

8. What causes the weather?
The amount of solar energy received by an area by its location to the earth position and sun.
Water Vapor: it determine whether there will be precipitation. (rain, sleet, snow, or hail)
Cloud cover will hold water vapor.
Landforms & bodies of water: Water heats slowly but can retain heat, & land heat rapidly but loses heat quickly.
Elevation: As elevation increases, the air becomes thinner and loses is ability to hold moisture.
Air movement: winds move the air and the solar energy and moisture that it holds.

9. Precipitation: water vapor in the air (rain)
Convectional: hot climates, the sun heats the air, and warm air rises
Orographic: Associated in mts. Areas. Mountain block the passage of the air and cause it to rise. Windward receives the rain & on the leeward side is called rain shadow & does not received any water only dry air.
Frontal: Mid-Latitude,cold dense air pushes up warm, light air causing precipitation.

10. Convectional
                                                 

12. Frontal

13. Hurricanes Tornadoes Blizzards Droughts Floods
Weather Extremes: as air moves across the earth, warm and cool air collides with each other and they create weather.
Hurricanes
Tornadoes
Blizzards
Droughts
Floods

14. Hurricanes They are storms that form over warm, tropical ocean water.
Different names:
In Asia:typhoons,
Tropical cyclones
Australia: willy-willies
Philippines: baguios
Mexico:Chubascos
Different categories.
Stage 1 is just above 75 miles to stage 5, over 150 miles.
Danger: storm surges, flooding & high winds.
25 to 30 per yr., but only 3 to 6 make landfall.

15. Tornadoes
Or a twister, is a powerful funnel-shaped column of spiraling air.
They form quickly & without warning.
Born from strong thunderstorms, winds swirl counter-clockwise, & winds may reach speed of 300 miles per hour.
Usually small diameter & will last only a few minutes, but they have been know to be as wide as a mile & last for hours.
700 tornadoes each yr.
This is the oldest known photo of a tornado. It was taken on August 28, 1884 near Howard, South Dakota. The name of the photographer is not known.

16. Blizzards
Is a heavy snowstorm with winds of more than 35 miles per hour and reduced visibility.
Some areas because of their location will received as much as 37.5 feet of snow per year.

17. Droughts
A long period of time without rain or with very minimal rainfall.
Makes in hard on crops & results in reduced levels in water storage.
1930s, the Great Plains were known as “Dust Bowl” as 150,000 square-mile were hit with dust storms.

18. Floods When water spreads over land not normally covered with water.
Melting snow or rainwater will fill rivers until they reach a flood stage.
After a river cannot take water any more it will flows into surround areas called floodplain.