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Two page infographic from the Federal Emergency Management Agency.

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What to do before, during and after an earthquake. Make sure you click on the links under "Keep Reading" for detailed information about the topic.

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Know what to do to protect yourself during an earthquake.

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What to do before, during and after a hurricane. Make sure you click on the links under "Keep Reading" for detailed information about the topic.

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About Hurricanes and Other Tropical Storms

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Know what to do to keep yourself and your loved ones safe before, during, and after the storm.

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What to do before, during and after a blizzard. Make sure you click on the links under "Keep Reading" for detailed information about the topic.

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Winter Weather: Before, During, and After

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Learn how to prepare for winter storms and protect yourself during all stages of a winter storm.

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What to do before, during and after a volcano. Make sure you click on the links under "Keep Reading" for detailed information about the topic.

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Know how to prepare for and protect yourself during and after volcanic eruptions.

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Two page infographic from the Federal Emergency Management Agency.

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Two page infographic from the Federal Emergency Management Agency.

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Two page infographic from the Federal Emergency Management Agency.

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Two page infographic from the Federal Emergency Management Agency.

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Two page infographic from the Federal Emergency Management Agency.

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Answers the questions about the causes, size and speed of a tsunami.

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They can speed across the ocean as fast as a jet plane, swallow up islands and wipe out villages.

But what causes tsuamis...? Join National Geographic Kids and dive into our tsunami facts to find out!

What causes a tsunami?

Meaning " great harbour wave" in Japanese, tsunamis are sometimes called "tidal waves" but their strength has nothing to do with the tides. About four out of five tsunamis happen within the Ring Of Fire, a zone in the Pacific Ocean where earthquakes and volcanic eruptions frequently take place.

Giant slabs of the Earth's crust, called tectonic plates, grind together. Sometimes, though, the plates get stuck, the pressure builds up and they suddenly slam into a new position. This causes an earthquake. If an earthquake lifts or drops part of the ocean floor, the water above rises and starts spreading across the ocean, causing a tsunami. Underwater landslides or volcanic eruptions can also displace water (cause water to spread across the ocean) and may lead to a tsunami.

How big is a tsunami?

Out in the open ocean, tsunami waves are only about one-metre high because the water is deep. However, as the water becomes shallow, the waves slow down and begin to grow. They can rise 35m or higher - that's the same as a 10-floor block of flats! However, the scariest thing about a tsunami is its wavelength, as this determines how far inland it can travel. Whereas a large wave caused by a storm might have a wavelength of up to 150m, a tsunami could reach up to a fearsome 1,000km!

How fast is a tsunami?

A normal wind wave travels at about 90kmh, but a tsunami can race across the ocean at an incredible 970kmh! Sometimes, before a tsunami hits, there is a huge vacuum effect, sucking water from harbours and beaches. People can see the ocean floor littered with flopping fish and other sea animals. Then a wave blasts onto the shore minutes later, then another and another for two hours or more. There may also be up to one hour between each wave.

Can you predict when a tsunami is coming?

To save lives, scientists established the Pacific Tsunami Warning System, based in Hawaii, in the USA. Its network of detectors can track quakes that may cause a tsunami. These waves can race from one side of the Pacific Ocean to the other in less than a day, so people need to be warned in time to head for higher ground!

What do you think of these tsunami facts? Let us know by leaving a comment, below!

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Tsunami facts: check out the mighty wave! - National Geographic Kids

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Check out these epic tsunami facts from National Geographic Kids! How do tsunamis form? And how big are they? Find out all about them in our tsunami facts...

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National Geographic Video About Tsunamis

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National Geographic Video About Tsunamis

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Three minute video with facts about tsunamis.

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Find out how a tsunami is born ... and how it destroys.

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Information about the deadliest tsunami...the Indian Ocean tsunami in 2004.

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The Indian Ocean tsunami that occured in December 2004 was the deadliest in history

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Information about blizzards and their dangers.

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Snow whirling around in wind blowing faster than highway speed limits makes the whole world look white. Imagine snow so deep that second graders can't see over the top of it. The wind and the snow may cause a power outage and collapse roofs. That's what you can expect from a blizzard.

What Is a Blizzard?

The National Weather Service defines a blizzard as a storm with large amounts of snow or blowing snow, winds greater than 35 mph (56 kph), and visibility of less than ¼ mile (0.4 km) for at least three hours. Some blizzards, called ground blizzards, have no falling snow. Instead, snow that had fallen before the blizzard is blown around or drifts in a way to create these conditions.

Blizzard conditions usually build up on the northwest side of a powerful storm system. The storm produces ample snow while strong winds develop because of a difference in pressure between the low pressure of the storm and the high pressure beyond the storm.

Conditions during a blizzard can be severe. Travel becomes dangerous when the blowing snow causes whiteout conditions and sky and ground look white. Roads can be partially or fully blocked by snowdrifts - piles of snow formed by the wind. Many times cold temperatures that can cause frostbite or hypothermia are part of a blizzard and can last for days after the storm has ended.

Where Do Blizzards Occur?

In the United States, blizzards are common in the upper Midwest and the Great Plains but occur in most areas of the country except for the Gulf Coast and the California coast. Blizzards can occur all over the world, even in the tropics where it is cold on high altitude mountaintops.

What a Blizzard Needs

Three things are needed to make a large snowstorm or blizzard:

1. Cold air (below freezing) is needed to make snow.
For snow to fall to the ground, the temperature must be cold both up in the clouds where snowflakes form and down at ground level. If the air near ground level is too warm, the snow will melt on its way down, changing to rain or freezing rain.

2. Moisture is needed to form clouds and precipitation.
Moisture in the air is called water vapor. Air blowing across a body of water, such as a large lake or the ocean, is an excellent source of water vapor. As wind moves air over the water, some water evaporates from the surface, putting vapor into the air. This is how lake effect snowstorms and nor'easters pick up so much moisture. However, cold air is not able to hold much water vapor. In fact, very cold air does not make very much snow.

3. Moist air needs to rise over very cold air, making clouds and snow.
There are two ways that moist air might rise over cold air. Winds pull cold air toward the equator from the poles and bring warmer, moist air toward the poles from the equator. When warm air and cold air are brought together, a front is formed and snow can form. Warm air can also rise to form clouds and blizzard snows as it flows up a mountainside.

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High winds can send snow flying through the air, reducing visibility and causing power outages. That's just some of what you can expect from a blizzard.

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Lots of information on tornadoes, including how to prepare for them and recovering after a tornado. Make sure to click the links/tabs on the left side of the page to go to additional information.

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OSHA is a Weather-Ready Nation Ambassador committed to working with NOAA and other Ambassadors to strengthen national preparedness for and resilience against extreme weather.

Introduction

Tornadoes can occur with little or no warning. Taking precautions in advance of the storms, such as developing an emergency plan, learning the warning signs, and monitoring tornado watches and warnings, can help you stay safe if a tornado occurs in your area.

OSHA and NOAA are working together on a public education effort aimed at improving the way people prepare for and respond to severe weather. This page is designed to help businesses and their workers prepare for tornadoes, and to provide information about hazards that workers may face in the aftermath of a tornado.

To prepare for a tornado, businesses should develop an emergency plan. The plan should include details on suitable places to take shelter, policies to ensure all personnel are accounted for, and procedures for addressing any hazardous materials that are on-site. It is also recommended that individuals develop action plans for their families.

The Checklists and Resources pages offer a simple way to make sure that you are prepared for a tornado, including suggestions for communications equipment and personal preparedness kits.

After a tornado has occurred, as businesses take steps to recover from the storm, workers may face significant hazards including the potential for additional storms, downed electric lines, and sharp debris. Workers should also be aware of hazards from heat stress and from equipment used during response/recovery operations, such as portable generators. Workers will need to take special precautions in order to stay safe during response and recovery operations. The Response/Recovery page has more information on these hazards and protections workers should employ.

Employer Responsibilities

Each employer is responsible for the safety and health of its workers and for providing a safe and healthful workplace for its workers. Employers are required to protect workers from the anticipated hazards associated with the response and recovery operations that workers are likely to conduct. For additional information on Workers' Rights, Employer Responsibilities, and other services OSHA offers, visit OSHA's Employers Page, Workers Page and Publications.

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Tornado Preparedness and Response - Introduction | Occupational Safety and Health Administration

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Introduction Tornadoes can occur with little or no warning. Taking precautions in advance of the storms, such as developing an emergency plan, learning the warning signs, and monitoring tornado watches and warnings, can help you stay safe if a tornado occurs in your area.