Weather & Climate Severe Weather

Objectives List and describe the main types of storms and explain how they form. List and describe basic safety for severe weather situations.

STORMS A storm is a violent disturbance in the atmosphere. They involve sudden changes in air pressure. Changes in air pressure causes rapid air movement.

Thunderstorms Formation W/in large cumulonimbus, or thunderheads Form when warm air is forced upward at a cold front Temperature Hot, humid afternoons in the spring and summer Precipitation Heavy rainfall Sometimes hail Safety Avoid touching metal objects Install metal lightening rods Find a low area away from trees Stay away from water

Thunderstorms During a thunderstorm, positive and negative electrical charges build up in the clouds. The discharge of the electricity between clouds is lightening. Lightening is as hot as 30,000°C, hotter than the sun. The heated air expands and explodes producing thunder.

Tornado Rapidly whirling, funneled-shaped cloud that reaches down from a storm cloud to touch Earth’s surface Most frightening & disruptive storm Usually brief, touching the ground approx. 15 minutes or less Wind speeds may reach 480 km/hr

Tornado Formation Develop in low, heavy cumulonimbus clouds When warm dry air mass and cool air mass collide Temperature Warm humid air Spring and early summer when ground is warm Precipitation Heavy rain and wind Safety Listen for watches & warnings Basement level, or to the middle room on ground floor Stay away from windows Lie in a ditch

Tornado Tornado Watch – tornadoes are possibly in your area Tornado Warning – tornadoes have been seen in the sky or on weather radar Occur most often in the US Approx. 800 tornadoes a year

Checkpoint Where do tornadoes form? Why is there a tornado alley? What states make up tornado alley? Low heavy cumulonimbus clouds Warm humid air mass moves north from Gulf of Mexico and meets a cold dry mass that is moving south from Canada SD, Iowa, Nebraska, Kansas, Missouri, Oklahoma, TX, NM, and Arkansas

Hurricanes Tropical storm that has winds of 119 km/hr Usually occur between June and November in the eastern US

Hurricanes Formation Begins over warm water as a low pressure area, tropical disturbance Gets it energy from warm humid air at the ocean’s surface Temperature Warm temperatures Precipitation Strong winds Rain which generally causes flooding Safety Evacuate Move into the interior room and stay away from windows

Hurricanes Occur between June and November Effect people that live on the coast of the Atlantic, Pacific, and Indian Oceans Eye – center of a hurricane

Winter Storms Lake-effect Snow – In the fall and winter, land cools faster than the lakes. When cool air mass moves from Canada across Great Lakes it picks up water vapor and heat from lakes. After the air mass passes the lakes it begins to cool and the water vapor condenses and falls as snow

What is it? A Blizzard is a blinding snowstorm with very strong winds and cold temperatures

When do they take place? Blizzards are storms that happen in the winter months.

How do they occur? Blizzards occur when a warm air mass runs into a cold air mass. Clouds form and the cold air freezes the moisture in the warm air mass. The wind speeds increase and snow falls to the ground.

Where do they take place?

Find shelter indoors. 2. Stay away from windows and doors. 3. If you are stuck in a car with the engine running to stay warm, keep the windows open a little bit. This will let poisonous carbon monoxide escape from the inside of the car. 4. Keep extra food and water, flashlight, a battery-operated radio, and, if possible, a cell phone with you. 5. If you are trudging through deep snow, keep moving. Do not lie down to rest. 6. If you are caught outdoors, use clothing to cover your face and as much of your skin as you can. Safety Precautions

Your Assignments You will work in predetermined groups. Within your group, you will create a skit demonstrating your knowledge on severe weather safety. –What is your severe weather? –How does it occur? –What are the safety precautions you should take if you are inside/outside? 1. group leaders (directors) 2. researchers (computer) 3. recorders (write everything down)