STORMS

Weather jokes?

Shoulder Partner Describe to your partner the scariest storm you’ve ever been in and what took place.

Close Encounter!

Types of storms… Storms – a violent disturbance in the atmosphere. Rain/Snow storms – formed when two different fronts collide (warm meets cold) Summer = steady rain Winter = heavy snowfall Blizzard = wind must reach 36 km/hr and be -7 degrees Celsius. Ice storm = rain freezes instantly. * Thunderstorms – cold meets warm front forming heavy rainstorms with thunder and lightning, has violent down drafts and strong wind shear.

Face Partner Which type of storm do you believe is the most deadly, meaning that is takes the most lives?

Ice Storms…

Lightning Lightning – sudden discharge of static electricity (cloud to cloud; cloud to ground) Leading cause of forest fires. Can strike people, animals, or buildings. When the air is heated by lightning it expands quickly resulting in loud sound waves (thunder). Safety – avoid open spaces outside; don’t go under trees for shelter, and avoid sinks, bathtubs, televisions, and telephones while inside during a lightning storm. If you hear thunder 3 seconds after a flash of lightning; the storm is only 1 km away.

Lightning continued…

Table Talk… What is a cyclone?

Cyclones and Anticyclones? Cyclones – any area of low pressure containing rising warm air. Causes rainy stormy weather. Anticyclones – any high pressure area. Causes dry, fair weather.

Now for a laugh!

Hurricanes Hurricanes – power cyclones that forms over tropical areas. Typhoon – hurricane that forms over the W. Pacific ocean. The rapidly, spinning rising air forms a donut-shaped wall of strong winds, clouds, and rainfall. The eye of the storm is always calm. (speeds of 74 to over 155 m/hr) Considered the most powerful of all storms.

Hurricanes and Typhoons

Map of a hurricane…

How are hurricanes categorized? The Saffir-Simpson Scale

Storm Chasing

Shoulder Partner… Would you ever go on a storm chase? Why or why not?

Tornadoes Tornadoes – incredibly destructive; a whirling, funnel-shaped cloud of low pressure. Develops in heavy cumulonimbus clouds. Acts like a giant vacuum cleaner, due to the low pressure. Not sure how they form, usually in the spring in late afternoons or evenings. Most common in the United States.

Map of a tornado…

Tornadoes continued…

More about tornadoes… Great Plains is “tornado alley”. Average diameter of a tornado is.4 km Average length traveled – 6 km for only a few minutes. Winds can still reach more than 350 km/hour. Measured on the Fujita scale as F0 – F5. (five being the strongest).

Tornado alley?

Fujita Scale

Precipitation types and Clouds

Can weather predict disaster?

Types of clouds… Cumulus –(cotton balls) are fluffy and white with flat bottoms. Indicate fair weather. Cumulonimbus – (thunderclouds) when cumulus clouds grow vertically and darken. Stratus – gray clouds that cover the whole sky and block out the sun. Light rain and drizzle are usually associated with these clouds. Cirrus – feathery clouds. Sometimes called “mare’s tails”. Indicate that it will rain/snow in the next 24 hours.

Cumulus Cirrus Stratus Cumulonimbus sCumulus Stratus Cirrus

Odd-shaped clouds

Do you see what I see?

Even more…

Precipitation When water vapor in the clouds becomes too heavy, it can fall as rain, sleet, snow, or hail Cloud droplets must first increase in size until gravity pulls them down When droplets pass through extremely cold layers of air as they fall, they freeze and produce sleet Snow is formed when water vapor (gas) changes directly into a solid. Process is called deposition. Hail is formed within the cloud.

You are done!