Hazard Analysis


Washington County faces a wide array of hazards, each posing unique challenges for citizens, businesses, government,
and other organizations. To better understand the types of hazards we face, the severity of impacts they may cause,
and the level of risk they pose, Washington County has developed a hazard analysis, which is a component of the
Washington County Emergency Operations Plan (available in the plans section of this website).


Hazard Analysis Methodology

123RF hazard imageFrom a preparedness perspective, it's helpful to look at all of the potential
hazards in Washington County and rate them against one another.  This provides
context for the hazards and allows us to focus preparedness efforts in areas
where we are most at risk.  To accomplish this, a detailed analysis was conducted
that rated hazards using four criteria:

  • Event History (how many events in the last 100 years)
  • Vulnerability (percentage of population or property likely to be affected)
  • Maximum Threat (percentage of population or property that could be affected
    by a worse case incident)
  • Probability (likelihood of occurrence within the next 10, 50, or 100 years)


Our Highest Risk Hazards

The Washington County hazard analysis indicates the following hazards, listed in order of descending risk, pose the
greatest risk–winter storm, flood, windstorm, earthquake, pandemic disease outbreak, utility failure, terrorism/civil
disturbance, drought, ash fallout (from a volcanic eruption), hazardous material release, wild land fire, dam failure,
transportation incident, tornado, and landslide.


Learn More About Hazards

The important lesson to learn from the hazard analysis is that while some hazards are more likely to affect us than
others, all are capable of negatively affecting us and all are possible in Washington County;therefore, it's important
we take measures to prepare for them. To learn more about hazards in our area, check out the Oregon Department
of Geology and Mineral Industries Statewide Geohazards Viewer, HazVu.