Severe Weather Notes
What is Severe Weather?
 Severe weather is any dangerous atmospheric event that has the potential to do damage to human life or
property.
 Some main types of severe weather include thunderstorms, snowstorms, ice storms, hurricanes, tornadoes,
floods, and droughts.
 Severe weather can take the form of high winds, hail, heavy rain, lightning storms, tornadoes, hurricanes, or
other events.
 Approaching severe weather patterns can sometimes be predicted from the thickness of low-altitude clouds.
 Severe weather happens on relatively short timescales and at particular locations.
Thunderstorms
 A thunderstorm is a type of severe weather that brings hail, lightning, thunder, heavy rain, and strong winds.
 Thunderstorms can cause flooding, fires (from lightning), or downed power lines.
 In a thunderstorm, it is best to stay inside and not to stand under trees.
Hurricanes
 A hurricane is a large storm that forms over the ocean. It is made up of very strong winds (over 74 mph), which
spiral inward.
 The center of a hurricane, or the "eye," is usually the calmest part of the storm.
 Hurricanes produce strong winds, heavy rains, and large waves on land.
 These can all cause damage to buildings, habitats, and wildlife.
 If enough advance warning is provided before a severe hurricane, the best course of action for anyone in the
immediate path of a hurricane is to gather loved ones, evacuate the home, and leave the city.
 It is also a good idea to shut off gas valves before leaving. Boarding up windows or positioning sandbags can help
to minimize the damage done to a home, but should only be done if local authorities recommend it.
 Local authorities will notify an affected population if and when an evacuation should occur.
Tornadoes
 A tornado is a type of severe weather known for its funnel-shaped cloud and high winds.
 Very violent tornadoes can reach wind speeds of up to 300 mph.
 Tornadoes can cause damage to buildings, cars, bridges, and trees.
 If a tornado is approaching, people should immediately take cover, stay away from windows, and stay in the
lowest level of the building they are in.
 If a person is caught outside during a tornado, he or she should seek cover in a building or lay flat on the ground
in a low area.
 It is generally not safe to be in an automobile during a tornado.
 Tornadoes are caused by updrafts of a thunderstorm that start to spiral.
Floods
 A flood can happen when rivers rise up to flow over their banks or when there are many days of heavy rains or
melting snow.
 Floods can harm plants and animals, destroy habitats, make driving difficult, damage homes, or even cause
drowning.
 During a flood, it is important to get to higher ground. Do not attempt to drive during a flood.
 If told to leave the area or evacuate, do so immediately.
Droughts
 A drought is an long period of time in which there is very little rain. During droughts, there can be a decrease in
the supply of drinking water.
 Having a back-up method of obtaining water could help during times of drought.
 Droughts cause harm to land because topsoil can be easily blown away when the ground is very dry.
 When a lot of dry soil is blown by the wind, it can even result in a dust storm.
 Droughts can harm habitats and ecosystems.
 When there is not enough water, plants and animals can become dehydrated and die.
 Also, dry, brittle plant material can easily catch fire, and huge wildfires can burn the rest of the plants in the
area.
 Without plants to eat, animals can become sick.
Snow and Ice Storms
 Snow and ice storms take place when large amounts of snow, sleet, or hail fall during times of cold
temperatures.
 When a severe snow or ice storm occurs, it is very important that people avoid traveling along roads or
highways.
 Since snow and ice can make these surfaces very slippery, controlling an automobile can become quite difficult.
 This is why automobile accidents are very common during snow or ice storms.