Natural Hazards

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Natural Hazards
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What is a natural hazard?
Unexpected variability in the timing, frequency,
magnitude, or location of environmental
phenomena.
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Environmental Phenomena

• Atmosphere
• Lithosphere
• Hydrosphere
• Biosphere

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Timing and Frequency

• Examples
• Temperature date of first and last frost
• Precipitation season and form
• Water resources
• Plant crops (germination and ripening)

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Magnitude

• Examples
• Precipitation (droughts, wet years)
• Temperature (heat waves, cold waves)
• Stream flow (floods, dry rivers)
• Groundwater (saturation, drying)
• Earth movement (earthquakes, erosion)
• Wildfires

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Location

• Examples
• Exotic species
• Mass movements
• River course changes
• Precipitation (or lack thereof)
• Heat and cold
• Wildfires

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Unexpected

• Depends on what we expect
• biophysically
• culturally
• socio-economically

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Group Activity Pick a Hazard discussed in your
textbook and evaluate it in terms of our model.

• What are the sources of variability that can
  create the hazard?
• What role does culture (including technology)
  play in setting thresholds for this hazard?
• What role does political economy play in setting
  thresholds for this hazard?
• How does each components affect interactions
  between the other two?

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Take-home Message

• Like resources, hazards can only be defined
  within particular cultural, political, economic,
  and geographic contexts.
• As those contexts change (demographics,
  economics, technology, environments), losses due
  to hazards are increasing dramatically.