3.2 - Tornada i cyklony tropikalne w Ameryce Północnej - 8SP dwujęzycz

Presentation by Daria Płatek

Tornadoes and tropical cyclones in North America

Quiz

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• identyfikuje skutki występowania tornad i cyklonów tropikalnych w Ameryce Północnej

Tornadoes and tropical cyclones are extreme events in North America. They cause unimaginable destruction and human casualties.

tornado

tropical cyclone

Tornado - a whirlwind (trąba powietrzna) that occurs in North America. It is a rapidly rotating column of air. It is formed when hot and humid air from the Gulf of Mexico meets cool, dry air from the Rocky Mountains.

A tornado is a dark funnel (lej) connected at its wider end to a storm cloud. There is a very large difference in atmospheric pressure between the center of the whirlwind and its edge. The pressure always tends to equalize, so there is a very strong wind - even 400 km/h.

Most tornadoes - over 1000 a year - occur in the United States, mainly on TORNADO ALLEY. It is a 650 km wide strip between .

WHAT DOES TONADO LOOK LIKE?The tornado looks like a funnel. There are lightning discharges in the upper part, and the lower part is surrounded by a cloud of dust and various debris. In the USA, tornadoes are usually 150 meters in diameter.

EFFECTS OF THE TORNADOSSince tornadoes are usually not very large and travel up to several tens of kilometers, it is sometimes possible to alert people who are on their way.The effects of tornadoes depend on their strength. The tornado intensity is determined by the EF SCALE (Fujita scale).

FORMATION OF TROPICAL CYCLONES

A tropical cyclone is a deep center of low atmospheric pressure. Cyclones form over highly heated oceans in the tropics (except the area of the Equator). The water temperature must exceed 25 degrees Celsius and be higher than the air temperature.

A tropical cyclone resembles a giant whirlpool. It can travel up to several thousand kilometers. In the center of the cyclone there is the EYE OF THE CYCLONE. It has a diameter of 20 to 30 km. There is no rain, the wind is weak and the sky is clear. There are huge cumulus clouds around the eye of the cyclone. There are also storms, heavy rainfall and very strong winds - up to 300km/h.

To identify tropical cyclones more quickly and to control their movement, they are given names. In the North Pacific female and male names are given to the cyclones in an alphabetical order. If a cyclone has been tragic, its name is never repeated again.

Tropical cyclones are found not only in North America but also in other parts of the world. However, they have other names:

• HURRICANES - in the Western Atlantic and Eastern Pacific Oceans
• TYPHOONS - in the north-wester Pacific
• CYCLONES - the Bay of Bengal, the Arabian Sea, South Indian Ocean
• WILLY-WILLY - north-west and north-east coasts of Australia

EFFECTS OF TROPICAL CYCLONES

The largest tropical cyclones cause many human casualties and enormous material losses. This is because they are usually found in densely populated areas with developed infrastructure. There are 3 main factors that influence the amount of losses:

• tremendous speed and strength of winds (they can even destroy entire buildings)
• intense rainfall (up to several thousand millimeters - several times more than in Poland throughout the year); rainfall leads to floods
• flood wave (up to several meters high)

https://www.youtube.com/watch?v=bnY1Zwxei_w

Tropical cyclones do not move too fast - up to 40 km/h. This allows the population to be warned and evacuated earlier.

Evacuation before the "Irma" hurricane

The strength of the cyclone is determined by the Saffir-Simpson scale.

Hurricane Katrina was formed over the Caribbean Sea near the Bahamas in 2005. As a result, over 1,800 people died (despite the evacuation), and material losses amounted to $ 100 billion.

As a result of the impact of a high flood wave, 80% of New Orleans was under water. The damage was so great that some neighborhoods have not been officially opened to their inhabitants to this day.

Prepared by Daria Płatek

THAT'S ALL! :)

Prezentacja wykonana na podstawie podręcznika Nowa Era: Planeta Nowa 7, bazy Internetu, prezentacji p. Izy Kleinszmidt, portalu geografia24.pl.