1. Storms

2. What is a storm?
A violent disturbance in the atmosphere.

3. What is a storm? Cause rapid air movement
Involves sudden changes in air pressure
Cause rapid air movement
Conditions that bring one kind of storm in one area often cause other kinds of storms in the same area

4. A thunderstorm is a small storm often accompanied by heavy precipitation and frequent thunder and lightening.
A thunderstorm forms when warm, humid air rises rapidly within a cumulonimbus cloud.

5. Types of severe storms
Thunderstorms
Tornadoes
Snowstorms
Hurricanes

6. Severe Thunderstorms Torrential Downpours
Strong winds at greater than 58 miles per hour
Hail ¾ inch diameter (or larger)
Frequent lightning

7. Severe Thunderstorm Watch
Issued by National Weather Service
This means that conditions are favorable for a thunderstorm
Length is multiple hours.

8. Severe Thunderstorm Warning
Issued By Local Weather Service
Means a severe storm has been spotted by doppler radar
Usually lasts for only an hour

9. Lightning
A sudden spark or energy discharge, caused when electric discharges jump between parts of a cloud, nearby clouds, or between a cloud and the ground.
Because a lightening bolt can heat the air near to it close to 30,000 ̊ C, it causes the air to expand explosively. Thunder is the sound of the explosion. Since light travels faster than sound you see lightening flash then you hear thunder.

11. Properties of a Lightning
Temperatures of over 30,000C (much hotter than Sun’s surface)
Heated air expands suddenly and explosively making a sound of thunder.

12. Thunderstorm/Lightning Safety
Stay indoors, away from doors and windows.
Avoid objects that conducts electricity, such as metal objects and bodies of water.
Do not seek shelter under the trees.
Do not use phones with cords.
Remember: Cars are pretty safe…

13. Why do we see lightning before we hear thunder?
Because light travels much faster than sound.

14. Tornadoes
Tornado Alley

15. What is a tornado?
A tornado is a rapidly whirling, funnel shaped cloud that reaches down from a cloud to touch Earth’s surface.

16. How are tornadoes formed?
Same system that produces thunderstorms can produce tornadoes.
Late in the day, when earth’s surface is very warm, convection (the flow of heat through a material, causing hot parts to rise and cooler parts to sink) can get very strong. This can lead to a tornado.

18. Tornado Watch Tornado Warning A tornado has formed.
Conditions are favorable for a tornado to form
Tornado Warning
A tornado has formed.

19. Tornado Happenings
1. When the updraft in a convection cell is really strong, the air rushes in from all sides at high speeds.

20. Tornado Happenings
2. Air curves into a spin. This lowers the pressure even more. Air rushes in even faster, and the pressure gets even lower, and so on.
Like a skater who pulls her arms in close to her sides. The tornado spins faster and faster.

21. Tornado Happenings
3. As the tornado gets stronger, a funnel forms that can destroy anything in it’s path. The center of the tornado can reach speeds of 500 kilometers per hour (about 300 miles per hour) or more.

22. Where Do Tornadoes Happen?
Tornadoes happen where dry, cold air masses mix with moist, warm air masses.
More tornadoes occur in the United States than in any other country, especially in the area known as TORNADO ALLEY.

23. Grand Island, Nebraska June 3, 1980
A Famous Tornado
Grand Island, Nebraska June 3, 1980

24. On June 3, 1980, a series of tornadoes devastated the city of Grand Island, Nebraska. Seven tornadoes hit within a three hour period. The storm did massive damage and closed the city down for three days.

25. Tornadoes Alley Tornadoes Safety
About 800 tornadoes every year in the United States.
Tornadoes Safety
The safest place to take a shelter is in a storm shelter or the basement of a well-built building.

26. What is a snowstorm?
All year round, most precipitation begins in clouds as snow.
If the air is colder than 0 degrees all the way to the ground, the precipitation falls as snow.

27. Snowstorm Safety Try to find a shelter from the wind.
Cover exposed parts of your body and try to stay dry.

28. Hurricanes

29. Formation Regions

30. What is a hurricane?
A tropical storm that has winds of about 119 kilometers per hour or higher (200 miles per hour).
Storm usually doesn’t last for more than 7-10 days.
As it moves inland it continues to move across the land but it begins to weaken

31. Map Symbols

32. What Does a Hurricane Need in Order to Develop?
Needs warm water
time to grow
favorable upper level winds in the troposphere.

33. Typical Path

34. Naming System A list of names from A-W (excluding Q)
Alternate from male to female
6 lists, repeated in cycle
Big name storms retired, like KATRINA.

35. Hurricane Watch Hurricane Warning
A hurricane poses a possible threat within the next 36 hours
Hurricane Warning
Hurricane conditions expected within 24 hours

36. MEMORIZE!!! The Saffir-Simpson Scale
Scale developed to categorize the hurricane based on wind’s speed.
MEMORIZE!!!
Saffir-Simpson Wind Scale and Animations
Storm Surge Overview and Animations

37. Hurricane Safety Best plan is to evacuate Plan early in advance
Towns have voluntary evacuation during a watch, and some switch to mandatory during a warning.
Plan early in advance

38. IF you choose to stay…. Board all windows
Prepare Flashlights, avoid candles
Stay tuned to radio
Stay indoors

39. The End