Unit 4 Lesson 4 Severe Weather and Weather Safety Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 4 Severe Weather and Weather Safety It’s in the air… Differences in air pressure cause Earth’s winds and weather changes. Storms are natural disturbances in the atmosphere that involve air pressure, clouds, precipitation, and strong winds. Major types of storms are thunderstorms, hurricanes, tornadoes, and winter storms Each type has its own characteristics and dangers Copyright © Houghton Mifflin Harcourt Publishing Company 2

Take Cover! What do we know about thunderstorms? Unit 4 Lesson 4 Severe Weather and Weather Safety Take Cover! What do we know about thunderstorms? A thunderstorm is an intense local storm that forms strong winds, heavy rain, lightning, thunder, snow and sometimes hail or no precipitation at all. Thunderstorms are known as electrical storms. Characterized by the pressure of lightning and thunder. There are three basic stages to a thunderstorm. Copyright © Houghton Mifflin Harcourt Publishing Company 3

What do we know about thunderstorms? Unit 4 Lesson 4 Severe Weather and Weather Safety What do we know about thunderstorms? Stage 1 – Warm humid air rises in an updraft, creating cumulus clouds. Copyright © Houghton Mifflin Harcourt Publishing Company 4

What do we know about thunderstorms? Unit 4 Lesson 4 Severe Weather and Weather Safety What do we know about thunderstorms? Stage 2 – Ice particles may form at the top of the cloud. They fall and pull cold air down, creating a downdraft and heavy rain or hail. Copyright © Houghton Mifflin Harcourt Publishing Company 5

What do we know about thunderstorms? Unit 4 Lesson 4 Severe Weather and Weather Safety What do we know about thunderstorms? Stage 3 – The storm slows or ends as the downdraft prevents more warm air from rising. Copyright © Houghton Mifflin Harcourt Publishing Company 6

What do we know about thunderstorms? Unit 4 Lesson 4 Severe Weather and Weather Safety What do we know about thunderstorms? Lightning is an electric discharge that happens between positively and negatively charged areas. Electrical charges build up near the tops and bottoms of clouds as pellets of ice move up and down through the clouds. Thunder is the sound created by the rapid expansion of air along a lightning strike. Copyright © Houghton Mifflin Harcourt Publishing Company 7

Secure Loose Objects! What do we know about tornadoes? Unit 4 Lesson 4 Severe Weather and Weather Safety Secure Loose Objects! What do we know about tornadoes? A tornado is a destructive, rotating column of air with very high wind speeds that is often visible as a funnel-shaped cloud. They are produces by severe thunderstorms Horizontal winds at high altitudes can cause a thunderstorm to spin and create a tornado. Spiralling high winds and extremely low pressure are the unique features of tornadoes. Copyright © Houghton Mifflin Harcourt Publishing Company 8

What do we know about tornadoes? Unit 4 Lesson 4 Severe Weather and Weather Safety What do we know about tornadoes? Tornado Alley is the location in the Midwest where tornadoes are common. Tornadoes often occur in the spring and early summer. Winds may reach speeds of over 400 km/h. Copyright © Houghton Mifflin Harcourt Publishing Company 9

Plan Ahead! What do we know about hurricanes? Unit 4 Lesson 4 Severe Weather and Weather Safety Plan Ahead! What do we know about hurricanes? Hurricanes are huge, rotating storms that form over the ocean near the equator They produce strong winds, heavy rains, and large powerful waves and can cause severe flooding and damage from strong winds. A hurricane is a tropical low-pressure system with winds blowing at speeds of 119 km/h (74 mi/h) or more. Copyright © Houghton Mifflin Harcourt Publishing Company 10

What do we know about hurricanes? Unit 4 Lesson 4 Severe Weather and Weather Safety What do we know about hurricanes? Hurricanes form from thunderstorms fueled by the evaporation of warm ocean water. Winds spiral around the low-pressure center of a hurricane. High winds and tornadoes can result from hurricanes and cause massive damage. A storm surge is a huge mass of ocean water that gets pushed onto coastal areas, causing sea levels to rise several meters. Copyright © Houghton Mifflin Harcourt Publishing Company 11

Unit 4 Lesson 4 Severe Weather and Weather Safety Winter is coming... Winter storms are associated with quickly moving cold fronts They can produce high winds, very low temperature and can include blizzards, ice storms and large accumulations of snow. Copyright © Houghton Mifflin Harcourt Publishing Company 12

Be Prepared! What can people do to prepare for severe weather? Unit 4 Lesson 4 Severe Weather and Weather Safety Be Prepared! What can people do to prepare for severe weather? Severe weather can cause property damage, injury, and sometimes death. Hail, lightning, high winds, tornadoes, hurricanes, and floods are all severe weather events. Copyright © Houghton Mifflin Harcourt Publishing Company 13

What can people do to prepare for severe weather? Unit 4 Lesson 4 Severe Weather and Weather Safety What can people do to prepare for severe weather? Plan ahead by creating a storm supply kit that contains essential safety items. Listen to the radio or TV for storm updates such as watches and warnings of upcoming storms. Copyright © Houghton Mifflin Harcourt Publishing Company 14

What can people do to prepare for severe weather? Unit 4 Lesson 4 Severe Weather and Weather Safety What can people do to prepare for severe weather? A watch is given when conditions are ideal for severe weather. A warning is given when severe weather has been spotted or is expected within 24 hours. Follow flood safety rules by getting to higher ground and staying out of floodwaters. Copyright © Houghton Mifflin Harcourt Publishing Company 15

What can people do to stay safe during a thunderstorm? Unit 4 Lesson 4 Severe Weather and Weather Safety What can people do to stay safe during a thunderstorm? Seek shelter if you hear thunder. Stay away from tall buildings and trees. Stay away from ponds, lakes, and bodies of water. Avoid using electrical appliances, phones, and running water when indoors. Copyright © Houghton Mifflin Harcourt Publishing Company 16

How can people stay safe during a tornado? Unit 4 Lesson 4 Severe Weather and Weather Safety How can people stay safe during a tornado? Go to a place without windows, such as a basement, storm cellar, or closet. Avoid areas where flying objects may cause harm. If you are outside, lie in a ditch or low-lying area and protect your head with your arms and hands. Copyright © Houghton Mifflin Harcourt Publishing Company 17

How can people stay safe during a hurricane? Unit 4 Lesson 4 Severe Weather and Weather Safety How can people stay safe during a hurricane? Have a plan to leave the area and listen for storm updates. Secure loose objects and prepare your home. If told to evacuate, do so immediately. Copyright © Houghton Mifflin Harcourt Publishing Company 18

Use Sun Sense! How can people protect their skin from the sun? Unit 4 Lesson 4 Severe Weather and Weather Safety Use Sun Sense! How can people protect their skin from the sun? Melanin in the skin can help protect against ultraviolet (UV) radiation from the sun. Protect your skin from sunburn, even on cloudy days. Prevent sunburn by wearing sunscreen with a sun protection factor (SPF) of 30 or more. Copyright © Houghton Mifflin Harcourt Publishing Company 19

How can people protect themselves from summer heat? Unit 4 Lesson 4 Severe Weather and Weather Safety How can people protect themselves from summer heat? Heat exhaustion occurs when the body has been exposed to high temperatures for too long. Heat stroke occurs when the body loses its ability to cool itself by sweating. It is life threatening. Limiting outdoor activities and drinking lots of water can help prevent heat illnesses. Copyright © Houghton Mifflin Harcourt Publishing Company 20

How can people protect themselves from summer heat? Unit 4 Lesson 4 Severe Weather and Weather Safety How can people protect themselves from summer heat? Heat stroke symptoms include high body temperature, rapid pulse, shallow breathing, disorientation, loss of consciousness, and hot, dry skin. Heat stroke victims need emergency help. Copyright © Houghton Mifflin Harcourt Publishing Company 21