Mammatus clouds beneath a summer thunderstorm on the north shore of Lake Superior, Minnesota.

perilous planet
for more natural hazards photography.



Other Resources:

Nature's Fury (National Geographic DVD)

Restless Earth Collection (National Geographic DVD)


Perils of A Restless Planet: Scientific Perspectives on Natural Disasters (Ernest Zebrowski, Jr.)

Disasters by Design: a Reassessment of Natural Hazards in the United States (Dennis Mileti)

WHAT is a natural hazard?

A Natural Hazard is an unexpected or uncontrollable natural event of unusual magnitude that threatens the activities of people or people themselves. A Natural Disaster is a natural hazard event that actually resulted in widespread destruction of property or caused injury and/or death. Natural hazards are usually classified based on where they occur on the Earth. Atmospheric hazards are most often weather-related events, while geologic hazards happen on or within the Earth's surface. However, it is important to to understand that atmospheric hazards can trigger geologic hazards (such as a thunderstorm producing flooding), and geologic hazards can trigger atmospheric hazards (such as a volcanic eruption producing thunderstorms).

WHY should we be concerned about natural hazards?

In every person's lifetime, at least one natural hazard will likely have some impact on their life. On average, about 150,000 people are killed worldwide by natural hazards each year. Unfortunately, the economic cost of natural hazards is increasing dramatically. For example, In the 1990's, the average cost of all natural hazards in the United States doubled from $25 billion to $50 billion per year. Globally, losses from natural hazards are increasing partially due to the exponential increase in human population. This unprecedented number of people has reduced resource availability and forced people to live in marginal areas where natural hazards occur more frequently and often with greater severity. In many developed countries, loss of life is low but economic costs are extremely high. In developing countries, loss of life tends to be very high while economic costs are usually lower.

Besides the direct impacts of natural hazards, such as floodwaters destroying a house, there are usually many indirect impacts, such as floodwaters spreading disease for weeks after the initial destruction. Although these indirect impacts may be less obvious initially, they are often more costly and can add years on to the recovery time from a disaster. As people who live in communities that have been devastated by a natural hazard will often say, there is no such thing as a complete recovery - natural disasters can forever change our way of living.

It is important to be aware of natural hazards because human activities can increase how often a natural hazard occurs and how severe a natural hazard can become. For example, building on top of an unstable slope adds weight to the slope and will increase the probability of the slope collapsing. Understanding when, where, why, and how natural hazards occur is the first step in minimizing their impacts on our lives.

WHERE do natural hazards occur?

Everywhere. At least one type of natural hazard affects every location on Earth. To learn more about where a certain hazard usually occurs, go to INVESTIGATE.

WHO studies and monitors natural hazards?

Several different types of scientists study natural hazards. In the United States, many natural hazards researchers are geographers who study both natural hazards and their interactions with people. Atmospheric scientists (meteorologists and climatologists) study hurricanes, blizzards, tornadoes, and other weather phenomena. Geologic scientists focus on landslides, earthquakes, floods, and other events that happen at the Earth's surface. Social scientists and psychologists are interested in how people cope with natural disasters.

To help reduce loses from natural hazards, several U.S. Government agencies are actively involved in the monitoring and mitigation of natural hazards including:

• Federal Emergency Management Agency (FEMA)
• National Aeronautics and Space Administration (NASA)
• National Oceanic and Atmospheric Administration (NOAA)
• National Weather Service (NWS)
• United States Geological Survey (USGS)

HOW do we cope with natural hazards?

Mitigation is the process of lessening the impact of natural hazards before, during, and after a natural hazard. Each hazard requires a specific type of mitigation. In some cases, engineering solutions (such as an earthquake-resistant building) can be used to temporarily reduce the impact of a natural hazard. However, only two forms of mitigation work indefinitely: 1) education about what a hazard is and how to prepare for it, and 2) limiting or not allowing human activities where a hazard occurs (such as floodplains). To learn more about mitigation for a specific hazard, go to INVESTIGATE.

To learn more about how you can help your community be prepared for a natural hazard, go to HELP.

Looking for images of natural hazards?

perilous planet
is the image-based companion site to NaturalHazards.org.