This module features an audio and visual tour of sites affected by the Fort Collins, Colorado urban flood that occurred on 28 July 1997. The tour is led by Matthew Kelsch and includes eyewitness accounts of that night's events from John Weaver. This interactive virtual field trip module summarizes many of the important common aspects of flash floods occurring in urban environments. Full description.

This site provides answers to frequently asked questions about tornadoes. The questions are grouped into the following categories: the basics about tornadoes, tornado forecasting, tornado damage, tornado safety, historical tornadoes, tornado climatology, spotting and chasing, tornado research, and scientific references. Information on related concepts is linked within each section and can also be ... Full description.

The National Hurricane Center contains news of active tropical systems; a hurricane awareness section about the hazards of hurricanes and what you can do to help protect yourself, your family, and your property; links to regional tropical cyclone centers; tropical weather outlooks, marine forecasts, and Sea Surface Temperature analyses; blank hurricane tracking charts; and current season summaries ... Full description.

This collection of basic definitions and answers to questions about hurricanes and tropical cyclones includes how they form, how they are named, how intensities are measured, and how storms are forecast. Historical information, information on myths surrounding these storms, links to sites displaying real-time storm information, and safety tips are also included. Full description.

This website, from the 1998 PBS "Savage Earth" series, shows seismic waves from an earthquake that took place in Bolivia in 1994. The animation illustrates the way the earth's surface, core/mantle boundary and inner/outer core boundary reflect and deflect P- and S-waves. Full description.

This resource presents a brief overview of these violent tropical ocean storms. It covers the science, phenomenon, and effects of hurricanes, and includes videos clips that depict how hurricanes form, what they look like, and what kind of damage they can do. Full description.

This resource provides information about the science, phenomenon, and effects of tornadoes. Video clips include an outing with a tornado hunter, an interview with a tornado survivor, and an animation depicting the science of tornado formation. Full description.

This site provides general information about floods and dams. There are sections on the science, the phenomenon, and effects of floods. One video clip shows the Mississippi River at flood and non-flood levels. Another clip shows actual footage of a flood wreaking havoc on a populated area. Full description.

This portal features an alphabetical listing of links to standard and three-dimensional (3D) images of geological and natural history-related subjects in the National Parks of the United States. The 3D images are anaglyphs and require red and cyan 3D viewing glasses. These full-size images may be slow to download. Users can click on a national park to start an image tour, use a subject index, location ... Full description.

This report describes the relationship between shaking intensity of earthquakes and the nature of the geologic materials in the San Francisco Bay area. In general, deep, loose sediments such as bay mud, beach, dune, and stream deposits, and man-made fill are more susceptible to shaking than are harder materials such as granite. It also points out that the majority of development in the Bay area is ... Full description.