Weathering the Storm

Weathering the Storm

These are the major types of severe weather that

we will learn about today

• Thunderstorms

• Tornadoes

• Hurricanes

A storm is a violent disturbance in the atmosphere.

They involve sudden changes in air pressure, which cause rapid air movements

Thunderstorms are heavy rain storms accompanied by thunder and lightning.

ThunderstormsThunderstorms form within large cumulonimbus clouds, or thunderheads

Cold Front Warm Air

Most form when warm air is forced upward at a cold front. They can also form on hot, humid afternoons in the spring and summer.In both cases, this is when warm, humid air rises rapidly.

Watches- when conditions are favorable to produce a thunderstorm

Warnings- Issued when a thunderstorm has already formed and is happening

Lightning Areas of positive and negative electrical charges build up in the storm clouds during thunderstorms

Lightning is a sudden spark, or energy discharge, as these charges jump between the parts of a cloud, between nearby clouds, or between the cloud and ground

What causes thunder??Lightning can heat the air around it as high as 30,000C which is hotter than the surface of the Sun!!This heated air expands rapidly, suddenly, and explosively. Thunder is the sound of that explosion.

Why do I see lightning before I hear it?

Because light travels faster than sound, you will see lightning first! Think about a baseball game, you see the player hit the ball before you hear the crack of the bat.

Thunderstorm Safety Tips

• Avoid metal objects

• Stay out of water

• Avoid electrical appliances,

bathtubs or showers, and

landlines, which can all

conduct electricity

TornadoesA tornado is a rapidly whirling, funnel-shaped cloud that reaches down from a storm and touches Earth’s surface

Tornadoes develop in low, heavy cumulonimbus clouds

Tornadoes occur more often in the United States than any other country.

About 800 tornadoes occur in the US every year

The Great Plains often have the type of weather patterns necessary for tornadoesCold, dry air mass moves south from Canada and meets warn, humid air from the Gulf of MexicoA squall line of thunderstorms can develop and can produce ten tornadoes or more Tornado Alley includes north-central Texas, central Oklahoma, Kansas, and Nebraska, but any state could have a tornado

Would you live there??

Tornado SafetyTornado watch means that conditions exist that could produce a tornadoThis means that you should pay attention to weather reports in case the weather should worsen or produce an actual tornado

Tornado Warning means that a tornado has been spotted on radar on in person, and you should take cover in a safe place

During a tornado, a “safe place” would be the most interior room in a house on the lowest level, away from windows and doors.

Tornado Tornadoes are measured based on their

wind speed/damage. The Fujita scale is used to measure the

intensity of a tornado by examining the damage caused by a tornado after it as passed over an area

Hurricanes

HurricanesHurricanes begin as a low pressure area, or tropical disturbance , over warm water

Hurricanes get their energy from the warm, humid air at the ocean’s surface.

This air rises and forms clouds, drawing more air into the system

Winds spiral inward toward the low pressure inside

Inside the storm are bands of high winds and heavy rains

The lowest pressure and warmest air is at the center of the hurricane in the eye

The “Eye” of the hurricane is the center, “quiet” area. If you were to be in the path of this hurricane, you would notice that

the winds get stronger and rain heavier as the eye approaches. In the eye, there would be calm winds and maybe even a clear

sky.Then the eye would pass and the storm would resume, with the

wind blowing in the opposite direction

The Eye of the Storm

Storm SurgeOne of the most dangerous features of a hurricane is the storm surge.Low pressure and high winds of a hurricane can raise the water up as much as 6 meters above normal sea levelThe result is a storm surge, or dome of water that sweeps on shore

How bad is bad?

Hurricanes are measured based on the strength of their winds

They start as tropical depressions,

then advance to tropical storms, then advance to

hurricanes

Once winds are at least 74 mph, they are a Category 1

hurricane

Name of Hurricane CategoryFlorida Keys (1935) 5Hurricane Camille (1969) 5Hurricane Andrew (1992) 5

Strongest hurricanes in US history

Name of Hurricane Amount of Damage ($)

Katrina 81 billionAndrew 26.5 billionWilma 20.6 billion