Review of Severe Weather

1. Review of Severe Weather Standards: b. Relate unequal heating of land and water surfaces to form large global wind systems and weather events such as tornados and thunderstorms. c. Relate how moisture evaporating from the oceans affects the weather patterns and weather events such as hurricanes.

2. Thunderstorms : produced by a cumulonimbus cloud, usually producing gusty winds, heavy rain and sometimes hail. Formation/cause: • The sun warms the Earth, and the Earth warms the air above it through the process of conduction. The warm air rises by convection. Warm air rising through cooler air continues to rise and is called unstable air. The warm air rises, and at some point, condensation occurs high in the cloud. Precipitation occurs (rain and sometimes hail), and a cold downdraft forms as the rain falls. What is needed: • Moisture - to form clouds and rain. • Unstable Air - relatively warm air that can rise rapidly. • Lift - things like fronts, sea breezes and mountains can lift air to help form thunderstorms. • Thunderstorms can produce hail, heavy rain and thunder and lightning

3. Structure of Thunderstorms • Lightning • electric discharge that occurs between a positively charged area and a negatively charged area • Most dangerous part of the thunderstorm • Energy is released when lightning strikes and is transferred to the air causing it to expand rapidly and sending out sound waves • Thunder: • the sound that results from the rapid expansion of air along the lightning strike.

4. Safety (write 2-3 things) • Go inside. The most dangerous place to be during a storm is outdoors. A car offers some shelter, but do not touch metal. Avoid leaning against vehicles. Get off bicycles and motorcycles. • If you are outdoors, be the lowest point. Lightning hits the tallest object. Stay away from trees. Stay out of boats. Get out of the water. Lightning can strike the water and travel some distance beneath and away from its point of contact. Don't stand in puddles, even if wearing rubber boots. Rubber boots will not protect you from lightning. If there is no shelter, crouch in the open, keeping twice as far away from a tree as it is tall. • Stay away from windows, doors, porches, and metal objects. • Avoid plumbing fixtures. Stay out of the bathtub or shower. Do not wash your hands or do dishes or laundry. • Stay off the telephone if it has a cord. • Before the storm arrives, turn off and unplug unnecessary electrical equipment (such as TVs or computers) to prevent damage in case of a lightning strike. • Avoid contact with electrical equipment or cords during the storm. • Avoid lying on concrete floors and leaning against concrete walls.

5. Hurricanes Hurricanes: a tropical storms with winds over 74 mph. Formation/Causes: • Hurricanes gather heat and energy through contact with warm ocean waters. Water is evaporated from the sea, and the moisture powers the storm. A wind pattern forms near the ocean surface that spirals air inward. Bands of thunderstorms form, which allows the air to warm further and rise higher into the atmosphere.

6. Hurricanes • Low pressure area is in the center. • winds less than 38 mph= tropical depression • At 39 mph it is given a name to help track it • Winds at 74 mph or greater= HURRICANE • Source of energy for hurricanes is warm waters once it hits land or cooler water, the winds begin to slow down

7. Hurricane Season • In the Atlantic, Caribbean and Gulf of Mexico area and Central Pacific=June 1 to November 30 • In Eastern Pacific=May 15 to November 30

8. Structure of the Hurricane • The eye: • Located in the center of the hurricane • 20-30 miles wide • Develops when wind speed is 78 mph or higher • Cloud free area of sinking air and light winds that are not higher than 15 mph • Calmest part of the storm • As the storm gets stronger the eyes shrinks in size

9. Eye Wall: • Surrounds the eye of a hurricane • Winds can go as fast as 200 mph • Has tall thunderstorm clouds that produce heavy rain and strong winds • Has the most destructive side of the storm • Rain bands: • Curved bands of clouds that trail away from the eye wall I spiral form • Can produce heavy bursts of rain and wind

10. Hurricane intensity • Scale used to measure a hurricane’s intensity= Saffir/Simpson Scale • Category One -- Winds 74-95 miles per hour • Category Two -- Winds 96-110 miles per hour • Category Three -- Winds 111-130 miles per hour • Category Four -- Winds 131-155 miles per hour • Category Five -- Winds greater than 155 miles per hour • Anything above Category 3 is considered a major hurricane storm

11. Safety (write about 2-3 things) • Listen to a radio or television for weather updates. • If you are told to evacuate, do not hesitate. Be sure you keep your car filled with gas. • Protect windows and sliding glass doors with plywood or storm shutters. • Shut off your utilities -- water, electricity and gas. • Assemble a disaster supply kit with nonperishable food, water, a first aid kit, battery-powered radio, and other things you will need. • Follow precautions that you would during a thunderstorm, if there is lightning. • Do not drive across flooded roadways. • Stay clear of downed power lines, trees, debris. • If your electricity is out, use flashlights as a source of light. Candles are a fire hazard. • After evacuation, do not return until it has been declared safe.

12. Tornadoes :small, spinning column of air that has high wind speeds and low central pressure and that touches the ground. Formation/Causes: • Develop from thunderstorms • beginning as a funnel cloud that pokes through the cumulonimbus cloud and touches the ground

13. Tornadoes • Most violent severe weather • Can have miles of to 300 mph • Can occur anywhere in the state but mostly occur in Central areas of the United States. • Tornado Watch=conditions make it possible for a tornado to occur • Tornado Warning=a tornado has been spotted • Scale used to measure=Fujita scale

14. Safety (write about 2-3 things) • Listen to the radio or watch TV for weather updates. Tornadoes are hard to predict. You may only have a few minutes warning. • Seek shelter if a tornado is coming your way. An underground shelter is best (basement or storm shelter). Or find an inside room or hallway or closet on the lowest floor away from windows. • If you are outside and cannot get inside, lie flat in a ditch or ravine. Lie face down and cover your head with your hands. • If you are in a car, take shelter in a nearby building. • After a tornado, watch for broken glass and downed power lines. If people are injured, don’t move them unless they are in immediate danger. Call for help right away!