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Term Definition
Consequence The impact of a disruption of a site’s mission(s). The severity of impact associated with a scenario in which a threat or hazard is realized and protective safeguards fail.
Continuity of Operations (COOP) An effort to ensure primary mission-essential functions continue to be performed during a wide range of emergencies, including localized acts of nature, accidents, and technological or attack-related emergencies.
Criticality weighting A relative-importance measure of the importance of a function to the accomplishment of a site’s critical missions.
Critical Functions The operations and activities required to enable a critical mission (e.g., a data center’s critical function is to process data for scientific analysis). Critical functions are enabled by critical loads (e.g., a chiller is a load that provides cooling to allow the data center to meet its critical function).
Critical Loads The energy or water loads that are required to enable critical functions. These depend on the supply of energy or water and can be impacted by a disruption to these systems.
Critical Mission A mission of such high importance that its incapacitation or destruction would have a severely degrading effort on the ability of the agency to execute the tasks or mission-essential tasks it supports in all operating environments. A critical mission is supported by critical functions, which are enabled by loads (e.g., facilities, systems, equipment, and resources).
Dependencies Systems, processes, or people that rely on another entity or system to perform a specific function. For example, water systems typically rely on energy systems for treatment and distribution. When power is disrupted, it is essential to understand the cascading impacts on those non-energy specific, but reliant, processes.
Dual-Impact Hazard or Threat A hazard or threat that impacts both offsite energy or water supplies and onsite redundant systems. The TRN allows users to identify dual impact hazards that should be assessed separately from other causes of energy or water outages.
Energy and Water Resilience Planning

Key elements and outcomes of energy and water resilience planning include:

  • Optimized operations to reduce energy and water use, as well as peak demand, that enable the site to meet energy and water requirements
  • Trained personnel and capabilities to anticipate, prepare for, adapt, withstand, respond to, and rapidly recover from energy and water disruption due to planned and unplanned events
  • Actionable strategies for diverse solutions that address resource and infrastructure needs to minimize the consequence of interruptions of energy and water services to critical missions and functions during normal and disrupted operations.
Energy and Water Resilience Planning Key elements and outcomes of energy and water resilience planning include:
Frequency The recurrence of a hazard or threat. In the TRN, frequency refers to the number of times the hazard or threat is expected to occur each year (annual frequency), and is analogous to probability.
Grouped Hazard A hazard or threat that impacts only offsite energy or water supplies. The TRN allows users to identify grouped hazards that cause a given outage duration for analysis without analyzing separately in cases where they have the same consequence.  This is also known as an all hazards approach.
Hazard A natural or accident-based driver with the potential to disrupt a site’s mission(s). Examples of natural hazards include earthquakes, storms, and wildfires.  Examples of accident-based hazards include dam failures, train derailments, and industrial accidents. In the TRN risk assessment, the hazard can refer to a specific hazard that causes an outage and impacts onsite systems (dual-impact hazard) or can refer to an outage event that impacts only offsite supplies (grouped hazard).  Hazard is quantified as the probability of a hazard being realized. In the TRN, hazards and threats are considered together.
Interdependencies A mutual reliance between two systems.
Likelihood Synonym for probability, likelihood is generally applied to the probability of a hazard or threat being realized or of the failure or success of safeguard (quantified as the vulnerability). It can represent a state of knowledge or a relative event frequency.
Mutual Aid Agreement Establishes the terms under which one party provides resources (e.g., personnel, teams, facilities, equipment, and supplies) to another party.
Natural Hazard Hazards associated with acts of nature such as severe weather (e.g., severe winter storms, floods, hurricanes, and storm surges). In the risk equation, the hazard refers to the probability of a hazard being realized.
Resilience Resilience refers broadly to the ability to anticipate, prepare for, and adapt to changing conditions and to withstand, respond to, and recover rapidly from disruptions through adaptable and holistic planning and technical solutions.
Resilience Gap A resilience gap exists where risk—as a function of hazards and threats, vulnerabilities, and consequence—exceeds a defined acceptable threshold or where conditions do not meet specific established resilience goals or standards.
Resilience Planning Resilience planning seeks to reduce potential impacts to operations from planned or unplanned disruptions via integrated and diverse solution sets. It is an iterative process that needs to be regularly revisited as a part of an organization’s operations.
Risk Risk is the potential for an unwanted outcome resulting from an event or sequence of events and is quantified in terms of the event likelihood and associated consequences. (Note: Within the TRN, consequence and impact are used interchangeably.)
Site A site is considered any collection of facilities (e.g., campus) or a single location (e.g., single building).
Technological Hazards and Threats Hazards associated with the potential for adverse impacts resulting from accidents or the failures of systems and structures to meet their design or operational intent (e.g., bridge collapse, grid outage). Could be due to random failures within a system or due to external influences, such as vehicle impact.
Threat An adverse event associated with malicious intent to create negative consequences. Sometimes the term threat refers to the likelihood of that threat being realized as an event. Threat is quantified as the probability of a threat being realized. In the TRN, hazards and threats are considered together.
Vulnerability The probability of a consequence occurring given that the hazard or threat has been realized. It is the probability that safeguards or protections intended to mitigate the hazard or threat fail. In the TRN, vulnerability is estimated through a characterization of redundant systems.
Vulnerability Assessment Evaluates the potential vulnerability of the critical assets against a broad range of identified threats and hazards. Determines the sensitivity of a system’s infrastructure to the realization of specific threats or hazards and the potential disruption or loss of that system. In the TRN, vulnerability is estimated through a characterization of redundant systems.
Weighting A numeric value that assigns a relative importance to an attribute that is being considered such as a risk category.