Lesson 17: Natural Hazards

Flooding near Olympia, WA, Dec 2007

Big Question:

Why Are More Of Them Becoming Disasters and

Catastrophes?

Lesson 17 / ESRM 100 / University of Washington

Case Study: Seattle Landslides

Rob Harrison photo

For more information and photos, see

Landslides in Seattle.

Lesson 17 / ESRM 100 / University of Washington

Hazards, Disasters, and Catastrophes

Lesson 17 / ESRM 100 / University of Washington

Taking a Historical Point of View

Lesson 17 / ESRM 100 / University of Washington

Fundamental Concepts Related to Natural Hazards•Hazards are predictable.•Links exist between different hazards and between the

physical and biological environment.•Hazards that used to cause mostly disasters are now

producing catastrophes.•Risk from hazards can be estimated.•Harmful effects of hazards can be minimized.

Lesson 17 / ESRM 100 / University of Washington

Nature’s Dual Role: Performing Natural-Service Functions and Posing Hazards

USGS photo

Lesson 17 / ESRM 100 / University of Washington

Natural Hazards Are Predictable

Mapping and monitoring are keys to spotting danger.

Sometimes it is possible to forecast an event and issue a

warning

Lesson 17 / ESRM 100 / University of Washington

Indonesian tsunami of 2004

An Indian Ocean tsunami warning system would have

triggered warnings automatically.

Lesson 17 / ESRM 100 / University of Washington

Lessons Learned

Lesson 17 / ESRM 100 / University of Washington

Linkages Between Hazards and Between the Physical and Biological EnvironmentsHazards may be linked

• Volcanic eruptions often cause landslides.• Mount St. Helens altered landscape and

ecosystems.

Lesson 17 / ESRM 100 / University of Washington

Hazards That Used to Produce Disasters Now Produce Catastrophes

Lesson 17 / ESRM 100 / University of Washington

Hurricane Katrina: One of the WorstNatural Catastrophes in U.S. History

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The city’s spread into low areas made it vulnerable to

flooding.

Lesson 17 / ESRM 100 / University of Washington

The Cost of Hurricane Katrina

•Warnings were given, but funds were lacking.•The whole New Orleans area is subsiding.

Lesson 17 / ESRM 100 / University of Washington

Estimating Hazard Risk

•Determine the probability of an event•Estimate the cost of a disaster•Estimate risk - Scientific or mathematical theory and

previous history•Progress in forecasting•Estimate the negative consequences•Determine acceptable risk

Lesson 17 / ESRM 100 / University of Washington

Minimizing Adverse Hazard Effects

Active versus reactive response:

- anticipate hazardous events;

- be proactive; and

- fast response.

Lesson 17 / ESRM 100 / University of Washington

Impact and Recovery from Disasters and CatastrophesHazardous events may affect society directly and

indirectly.

Lesson 17 / ESRM 100 / University of Washington

Perceiving, Avoiding, and Adjusting to Hazards•People believe that bad things happen to others, not to

themselves.•Laws can protect people who disregard hazards.•Land-use planning to avoid hazards.•Obtaining insurance program•Implementing evacuation plan•Minimizing effects with preparation•Control through engineering

Lesson 17 / ESRM 100 / University of Washington

Disasters and Catastrophes in the FutureSignificant increase likely to continue with human

population growth.

Chapter 17: Natural Hazards

Flooding near Olympia, WA, Dec 2007

Questions? E-mail us at eschelp@uw.edu