4.3 Severe Weather Pages (R) Severe Weather Pages

Youtube videos Severe Storms NOVA PBS 3:38 Lightning 101 National Geographic 2:38 Mr. Parr Thunderstorms Hurricanes 101 National Geographic 3:30 Mr. Parr Hurricanes and Twisters Tornados 101 NG 2:46 STORM CHASERS: Inside a tornado NG 4:15 Tornado Safety Tips by Martin Peters 4:54 Oklahoma Tornado 2013 (Strongest tornado ever recorded )

Severe Weather can cause major damage, injuries, and death thunderstorms, hurricanes, blizzards, and tornados

Severe Thunderstorms Dangerous storms that contain damaging winds, heavy rain, hail, thunder, and lightning

Weather conditions needed: - low pressure system - warm temperatures - moisture - an energy source of updrafts (air moving vertically up) and downdrafts (air moving vertically down)

Stages of a Thunderstorm 1. Cumulus Stage warm air rises and forms tall cumulus clouds the rising air creates updrafts the air condenses and forms precipitation

2. Mature Stage The cold upper air is dense and sinks causing downdrafts. The constant motion of up and downdrafts produces strong winds, heavy rain, lightning and thunder.

3. Dissipating Stage storm loses energy downdrafts continue, but updrafts slow and finally stop Rain and winds fade

Lightning electricity found in all thunderstorms strong updrafts/downdrafts cause millions of ice crystals to rise/sink. they bump into each other creating electrically charged particles

lightning can move within the same cloud between clouds and from cloud to ground

most people struck are not killed, but suffer major injuries and burns. they do not continue to carry an electrical charge after being struck kills or seriously injures 75 to 100 people yearly Florida has the most lightning strikes in the US

T hunder the sound heard after lightning as lightning travels through the air, it super- heats the air to a temperature of 27,000°C the air expands because of the intense heat once the lightning passes, air contracts and creates a sound wave

we see the flash of lightning before we hear thunder because light travels faster than sound. Lightning can be seen 100 miles away. Thunder can be heard up to 15 miles.

To estimate the distance of a storm: 1. begin counting when you see lightning 2. stop counting when you hear thunder thunder travels one mile in 5 seconds, therefore the storm is 1 mile away for every 5 seconds counted

Severe Weather Watch vs Warning a watch means severe weather is possible a warning means severe weather is already occurring

Thunderstorm Safety Tips go to a safe place immediately (sturdy building or car) Avoid metal objects and water (both good conductors of electricity)

Avoid tall objects, lightning usually strikes the highest point do not use electrical equipment wait at least 30 minutes before going back outside

HURRICANES largest type of severe storm with winds spinning counterclockwise exceeding 72mph

most destructive storms because of strong winds and heavy rain that cause flooding

Hurricane Formation Hurricanes form as thunderstorms off the coast of southwest Africa Warm ocean water provides the energy for hurricanes to develop

The hurricane begins to dissipate (break up) as it moves over land or cooler water

Atlantic Hurricane Season June 1 to November 30 most hurricanes occur in late summer (August-September)

Structure of a Hurricane The eye is the center of the hurricane and calmest part of the storm. The eye wall surrounds the eye and has the most damaging winds and heaviest rain. Rain bands are thunderstorms that extend from the eyewall. and spiral counterclockwise

Hurricane Safety keep an emergency kit with supplies ready take measures to protect your property and plan an evacuation route for your family

The National Weather Service provides updated information about the storm and issues watches and warnings data comes from satellite images or is airplanes that fly directly into hurricanes

hurricanes are given categories based on the strength of winds and amount of damage caused

Tornados Violent whirling columns of air extending from thunderstorms that come in contact with the ground Occur mostly in spring and summer

swirling winds begin to spiral downward from the base of the T-storm and creates a funnel cloud The storm becomes a tornado when it touches the ground

speeds can reach over 260mph causing severe damage and death

Tornado Alley is a name given to the area in the Midwest that experience the most tornadoes.

Storm Chasers people that observe and record weather data about tornadoes as they are happening

tornados are classified according to wind speed and damage F0-F5 a tornado watch means weather conditions are favorable and it is possible for tornados to form in the area a tornado warning means tornados have been sighted