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Sarpy County Hazard Analysis |
During the development of this hazard analysis, all events which could pose a threat to Sarpy County were analyzed and rated according to history, vulnerability, maximum threat, and probability. The events which were identified as high priority in terms of significant threat, and for which preparedness, planning and mitigation efforts are needed, are listed.
In determining and ranking hazards, the following criteria were used:
History - Each hazard was rated based on the number of occurrences in the county within the last 100 years.
Low = 0 to 1 occurrence
Medium = 2 to 3 occurrences
High = more than 3 occurrences
If the hazard was relatively new, or there was no history available, the history was rated as low.
Vulnerability - Estimates of vulnerability were derived by considering: where people live in relation to the hazard, what the land is being used for, and the value of the property in or near the risk area. The rating was then based on the percent of population which might be killed, injured, or contaminated; and all property that might be destroyed, damaged, or contaminated.
Low = less than 1%
Medium = 1% to 10%
High = more than 10%
Maximum Threat - Examines the “worst-case scenario” in terms of the worst conceivable impact to human life and property which could result from an occurrence.
Low = less than 5% of the population and property affected
Medium = 5% to 25% of the population and property affected
High = more than 25% of the population and property affected
Probability - Estimate of the likelihood that an event will occur in Sarpy County. Rated according to chances per year of occurrence.
Low = less than 1 in 1,000
Medium = 1 in 1,000 to 1 in 10
High = greater than 1 in 10
Each event was scored to identify high priority hazards. Each of the four criteria was assigned a numerical value depending on the rating (low, medium or high). Since some criteria are considered to be more important than others, a weighting factor was used to balance the total score.
| HAZARD | HISTORY | VULNERABILITY | MAXIMUM THREAT | PROBABILITY |
|---|---|---|---|---|
| Tornado | High | High | High | High |
| Ice Storm | High | High | High | Medium |
| Winter Storm | High | High | High | Medium |
| Thunderstorm | High | High | Medium | High |
| Railway Accident | High | Medium | High | Medium |
| Hazardous Material Storage | High | High | High | Low |
| Air Accident | High | Medium | Medium | High |
| Flood | High | Medium | Medium | High |
| Terrorist Activity | Low | Medium | High | Medium |
| Earthquake | Low | High | High | Low |
| Nuclear Attack | Low | High | High | Low |
| Hazardous Materials Transportation Spill | High | High | Medium | Medium |
| Industrial Accident | High | Medium | High | Low |
| Dam Failure | Medium | Medium | High | Low |
| Natural Gas Interruption | Low | Medium | High | Low |
| Nuclear Power Plant Incident | Low | Medium | High | Low |
| Flash Flood | High | Medium | Medium | Medium |
| Reception of Evacuees | High | Medium | Medium | Medium |
| Large Gatherings | High | Medium | Low | Medium |
| Health Threat-Major | High | Medium | Medium | Low |
| Highway Accident - Major | High | Low | Medium | Low |
| Fire - Grassland | High | Low | Low | Medium |
| Fire - Major Urban | High | Low | Low | Medium |
| High Winds | High | Low | Low | Medium |
| Power Failure / Shortage | Low | Low | Medium | Low |
| Civil Disturbance | High | Low | Low | Low |
| Water Failure / Shortage | Low | Low | Medium | Low |
| Communications Failure | Low | Low | Low | Low |
| Explosion | Low | Low | Low | Low |
*Hazards are rated in order of priority. The highest rated hazard is listed first.
Return to the Sarpy County Hazard Analysis Index
Created January 28, 1997
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