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IAEM AEM study materials
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IAEM AEM: Hazard Identification, Risk Assessment, and Vulnerability Analysis

IAEM AEM · Work through your exam, one topic at a time.

All guide sections

Hazard Identification, Risk Assessment, and Vulnerability Analysis

What this domain tests

HIRA questions test whether you can build a defensible risk picture from data and use it to drive planning, capability targets, and mitigation priorities.

Core rules

  • Standard steps: identify hazards; profile each hazard (frequency, magnitude, speed of onset, duration, location); inventory assets and population; estimate potential impacts; assess vulnerability; determine risk; communicate the results.
  • Risk is generally expressed as a function of probability (likelihood) and consequence (impact), with vulnerability and exposure shaping consequence. A matrix makes comparison explicit but hides the assumptions behind the scores.
  • THIRA (CPG 201) is not a hazard ranking exercise. Its three steps are: identify threats and hazards of concern; give them context through standardized scenarios; and establish capability targets stated against the 32 core capabilities of the National Preparedness Goal. The Stakeholder Preparedness Review then compares current capability to those targets and identifies gaps.
  • Data sources include historical events, insurance and damage records, GIS and land-use data, census and social vulnerability data, weather and seismic monitoring, and modeling tools such as HAZUS.
  • Cascading and concurrent hazards must be captured: a power failure after an ice storm, or a chemical release caused by flooding.

Worked example

Two hazards are scored on a 1–5 probability by 1–5 consequence matrix. Hazard A: probability 4 (likely within ten years), consequence 3 (moderate) = 12. Hazard B: probability 2 (occasional), consequence 5 (catastrophic) = 10. Hazard A ranks higher on the score, but B's catastrophic consequence may still justify dedicated planning. The defensible answer explains the scoring, the assumptions, and the limits of the matrix rather than treating the number as truth.

Traps

Confusing THIRA with a HIRA; scoring only probability; ignoring social vulnerability and access and functional needs; and forgetting that the HIRA must be refreshed as the community changes.