This text is part of the Weather Preparedness & Resilience Toolbox developed by the YOUROPE Event Safety (YES) Group within YOUROPE’s 3F project (Future-Fit Festivals). It is aimed at everyone involved in planning, building, and operating open-air events. It helps festivals and other outdoor events become truly weather-ready by offering both practical and research-based resources as well as background information on weather and climate. Learn how to design safer and more weather-resilient outdoor events.

Everyone knows what a “storm” is – but do we really? Do we really speak of the same phenomenom when we say, “there is a storm coming”? – Clear terminology does not only help to improve the understanding of the topic but also is – like clear thresholds – an important part of each risk assessment and each decision matrix.

Part of the Toolbox therefore is a practical glossary for weather-related planning and operations in events and festivals. Where applicable, entries include links to international standards and authoritative guidance.

Note: Access to full texts of standards may require purchase from the respective organizations.

A

• Acceptable risk The extent to which a [disaster] risk is deemed acceptable or tolerable depends on existing social, economic, political, cultural, technical and environmental conditions.
• Action plan Often called an ‘incident action plan’, this is a statement of intent that is specific to an incident or event. It details the response strategies, objectives, resources to be applied and tactical actions to be taken (WHO 2015a).
• Activation level A level of readiness or emergency response describing [an emergency operations centre’s] activities in response to predetermined criteria related to the severity of an incident (WHO 2015a)
• Adaptation (climate adaptation) Adjustments in systems and practices in response to climate change and variability to moderate damage or exploit beneficial opportunities. actuary​
• Adaptation Plan A documented framework for adjusting event operations based on forecasted or actual weather impacts (e.g., staged trigger actions for wind, heat, lightning).
• After-action report Document describing the response to an inci-dent and findings relating to performance of the [health system] response during an incident (WHO 2015b).
• After-action review After an activation, operation or exercise has been completed, a process involving a structured facilitated discussion to review what should have happened, what actually happened, and why (WHO 2015b).
• Alert Chain Defined communication pathway for escalating weather warnings between meteorological partners, event command, and operational teams.
• All-hazards approach An approach to the management of the entire spectrum of emergency risks and events based on the recognition that there are common elements [and common capacities required] in the manage-ment of these risks, including in the responses to virtually all emergencies.
• Anemometer Instrument measuring wind speed (and sometimes direction). Place on unobstructed masts near stages/structures for reliable readings.
• Atmosphere Layer of gases surrounding Earth in which weather occurs; typically divided into troposphere, stratosphere, mesosphere, thermosphere, and exosphere. wikipedia​

B

• Beaufort Scale Empirical wind scale (0–12) based on observed effects; often used to communicate thresholds operationally.
• Boundary layer (planetary boundary layer) Lowest part of the atmosphere directly influenced by the surface, usually the lowest 1–2 km, where friction, turbulence, and local effects (urban heat, terrain) strongly shape wind and temperature. sciencenotes​
• Briefing Protocol Structured briefing ensuring staff are aware of expected weather, triggers, roles, and contingency actions.
• Build back better The use of the recovery, rehabilitation and recon-struction phases after a disaster to increase the resilience of nations and communities through integrating disaster risk reduction measures into the restoration of physical infrastructure and so-cietal systems, and into the revitalization of live-lihoods, economies and the environment (UNGA 2016).
• Business continuity management An organization-wide discipline and a complete set of processes that identifies potential impacts which threaten an organization. It provides a capability for an effective response that safeguards the interests of its major stakeholders and reputation (ISO 22301:2012).
• Business continuity plan A document that describes how an organization will maintain and restore critical operational functions and services to a predetermined acceptable level in the event of an occurrence that disrupts its operational capabilities (WHO 2015a).

C

• Chain of command A series of command, control, executive, or man-agement positions in hierarchical order of authority (WHO 2015a)
• Climate change A change in the state of the climate that can be identified (for example by using statistical tests) by changes in the mean and/or the variability of its properties and that persists for an extended period, typically decades or longer (IPCC 2012).
• Climate change adaptation In human systems, the process of adjustment to actual or expected climate and its effects, in order to moderate harm or exploit beneficial opportunities. (IPCC 2012).
• Climate Long-term statistics of weather (typically 30 years or more) for a given region, including averages and variability of temperature, precipitation, and other variables. wikipedia​
• Climate system Interacting system comprising atmosphere, hydrosphere, cryosphere, lithosphere, and biosphere that determines Earth’s climate. wikipedia​
• Climate variability Natural fluctuations in climate variables over months to decades without implying a specific cause. actuary​
• Climate-related risk Potential adverse consequences for lives, livelihoods, health, assets, and infrastructure resulting from climate-related hazards combined with vulnerability and exposure. actuary​
• Cold debrief A debriefing session held after a period of time has passed following an exercise or incident, in order to discuss, with the benefit of hindsight, any observations and issues that may have been overlooked during a hot wash (WHO 2015a)
• Comprehensive emergency management Risk-based approach covering prevention, mitigation, preparedness, response, and recovery as a continuous cycle. ontario​
• Concept of operations A section or statement in an agency emergency plan that identifies policies, role and responsibilities, and how the structural or functional elements of the organization will work together to produce a coherent management response (WHO 2015a)
• Context As applied to emergency risk management, context is described by a number of factors related to the setting, circumstances and environment of risks and events.
• Contingency Area Designated space where attendees can shelter or be relocated during weather disruptions (hail, lightning, wind).
• Coping capacity The ability of people, organizations and systems using available skills and resources, to manage adverse conditions, risk or disasters.
• Crisis An unstable or crucial time or state of affairs in which a decisive change is impending, especially one where a highly undesirable outcome is distinctly possible (WHO 2015b)
• Critical infrastructure Assets, systems, and networks essential for the functioning of a society and economy (e.g., power, communications, transport, water). who​

D

• Direct economicloss The monetary value of total or partial destruction of physical assets existing in the affected area. Note: [For the purposes of Sendai Framework reporting],  direct  economic  loss  is  nearly equivalent to physical damage. Direct economic losses usually happen during the event or within the first few hours after the event and are often assessed soon after the event to estimate recovery cost and claim insurance payments. These are tangible and relatively easy to measure (UNGA 2016).
• Directly affected Those who have suffered injury, illness or other health effects; who were evacuated, displaced, relocated or have suffered direct damage to their livelihoods, economic, physical, social, cultural and environmental assets. (UNGA 2016).
• Disaster Serious disruption of the functioning of a community or society causing wide human, material, economic, or environmental losses exceeding the affected community’s ability to cope using its own resources. who​
• Disaster response Actions taken directly before, during or immediately after a disaster in order to save lives, reduce health impacts, ensure public safety and meet the basic subsistence needs of the people affected. (UNGA 2016).
• Disaster impact The total effect, including negative effects (e.g. economic losses) and positive effects (e.g. eco-nomic gains), of a hazardous event or a disaster. Note: The term includes economic, human and environmental impacts, and may include death, injuries, disease and other negative effects on human physical, mental and social well-being. (UNGA 2016)
• Disaster risk information Comprehensive information on all dimensions of disaster risk, including hazards, exposure, vulnerability and capacity, related to persons, communi-ties, organizations and countries and their assets. Note: Disaster risk information includes all studies, information and mapping required to understand the disaster risk drivers and underlying risk factors. (UNGA 2016)
• Downburst / microburst Localized, powerful downdraft from a thunderstorm that hits the ground and spreads out, producing damaging straight-line winds; microbursts are especially small (under 4 km) but intense. sciencenotes​

E

• Early warning and response (EWAR) The organized mechanism to detect as early as possible any abnormal occurrence or any divergence from the usual or normally observed frequency of phenomena.
• Early warning system Set of capacities to generate and disseminate timely and meaningful hazard warnings, enabling individuals and organizations to act in sufficient time to reduce harm. ipcc​
• Emergency information officer (EIO) Person responsible for acting as primary public and media contact for emergency-related information. ontario​
• Emergency response plan A document that describes how an agency or organization will manage its responses to emergencies of various types.
• Emergency Serious, unexpected situation that poses an actual or potential threat to life, health, property, or the environment and requires immediate action. ontario​
• Evacuation Organized, phased, and supervised movement of people from a dangerous or potentially dangerous place to a safer location. who​
• Exposure People, infrastructure, and assets located in hazard-prone areas and therefore subject to potential loss. actuary​.
• Extreme event (climate context) Occurrence of a value of a weather or climate variable above (or below) a threshold near the upper (or lower) ends of the observed range, such as heatwaves or heavy rainfall events. ipcc​
• Extreme weather Weather that is unusually severe or rare for a given place and time, such as violent storms, very high winds, heavy precipitation, heatwaves, or cold waves. wikipedia​

F

• Fog / mist Suspended water droplets reducing visibility near the surface; fog usually refers to visibility below 1 km, mist to slightly better visibility. canada​
• Front (cold, warm, occluded, stationary) Boundary between two air masses of different temperature and density; cold fronts bring advancing colder air, warm fronts advancing warmer air, occluded fronts where a cold front overtakes a warm front, stationary fronts move little. timeanddate​

G

• Global warming Ongoing increase in global average near-surface temperature, largely driven by rising greenhouse gas concentrations from human activities. dialogue​
• Greenhouse gases (GHGs) Atmospheric gases such as carbon dioxide, methane, nitrous oxide, and water vapor that trap outgoing longwave radiation and warm the climate system. wikipedia​
• Gust front Leading edge of cooler, denser air spreading out from a thunderstorm downdraft; can cause sudden wind shifts, strong gusts, and dust or debris clouds. weather​

H

• Hail Frozen precipitation in the form of balls or irregular lumps of ice produced in strong updrafts of thunderstorms, posing impact and injury risk for crowds. sciencenotes​
• Hazard identification Systematic process to recognize and describe relevant hazards that could affect a site or event. ontario​
• Hazard Source of potential harm or adverse effect on people, property, or the environment; can be natural (storm, flood), technological, or human-caused. ipcc​
• Heat index (apparent temperature) Combined effect of air temperature and humidity indicating how hot it feels to humans; used to assess heat stress risk. timeanddate​
• High pressure system (anticyclone) Region of higher atmospheric pressure associated typically with sinking air, lighter winds, clearer skies, and more stable weather. wikipedia​
• Hot debrief A debriefing session held immediately after an exercise or incident to identify the strengths and weaknesses of plans, policies and procedures. Note: In a hot debrief, participants and the exercise management team provide immediate feedback or a debriefing event. Individuals share perspec-tives on strengths, weaknesses, and areas for im-provement which are incorporated in the exercise report ((WHO 2015a), (WHO 2017c)).
• Hydration station / cooling station Designated area providing drinking water, shade, and sometimes active cooling to reduce heat stress risk. who​

I

• Incident Command System (ICS) Standardized on-scene management system with defined roles, processes, and terminology to coordinate responders and resources. macog​
• Incident Commander (IC)
  Person with overall responsibility for managing an incident, including setting objectives, strategies, and priorities. emsics​
• Incident
  Event, expected or unexpected, that requires an emergency response to protect life, property, or the environment. emsics​
• Incident management system System that defines the roles and responsibilities of personnel and the operating procedures to be used in the management of incidents (ISO 22300:2018).
• Interested party Person or organization that can affect, be affected by, or perceive itself to be affected by a decision or activity (ISO 22300:2018).
• Interoperability Ability of diverse systems and organizations to work together (ISO 22300:2018).

L

• Lead time Time interval between the issuance of a warning and the onset of hazardous conditions, crucial for evacuation and shelter decisions. ipcc​
• Lessons learned Identified issues for which remedial actions may be implemented, in order to improve performance (WHO 2015a)
• Lightning Protection Zone (LPZ) Defined protected area within a lightning protection system for structures and equipment.
• Local Meteorological Service (LMS) Accredited regional/on-site provider of meteorological information integrated with national services.
• Low pressure system (cyclone, depression) Region of lower pressure associated with rising air, clouds, wind, and often rain or storms; deeper lows generally mean more severe weather. timeanddate​

M

• Mitigation (prevention/mitigation) Structural and non-structural measures to reduce the likelihood or impact of emergencies and disasters (e.g., design standards, land-use planning, weather shelters). ontario​
• Monitoring In the context of surveillance and response refers to the routine and continuous tracking of the implementation of planned surveillance activities (monitoring the implementation of the plan of action) and of the overall performance of surveil-lance and response systems (WHO 2014)

N

• Nowcasting Very short-range forecasting (typically 0–2 hours ahead) using high-frequency observations like radar and local sensors; crucial for lightning and storm management at events. sciencenotes​

O

• Operational Weather Plan (OWP) Document defining roles, thresholds, data sources, and decision processes for weather management.

P

• People at risk Individuals who may be affected by an incident [or a hazardous event] (ISO 22300:2018).
• Preparedness Activities and measures taken in advance of an emergency to ensure effective response (planning, training, exercises, equipment, early warning procedures). ccaha​
• Public communication The discipline and process of providing public audiences with information that creates awareness and knowledge so that people can adjust their personal understanding of risks, and their reactions, decisions and responses to threats and crisis situations (WHO 2015a)
• Public warning message Official communication that provides information about a hazard, its expected impacts, the affected area, timing, and required protective actions. who​
• Public warning system Set of protocols, processes and technologies based on the public warning policy to deliver notification and alert messages in a developing emergency situation to people at risk and to first responders (ISO 22300:2018).

R

• Rapidresponseteam A group of trained individuals that is ready to responds quickly to an event (WHO 2018a).
• Readiness The ability to quickly and appropriately respond when required (UNGA 2016).).
• Recovery Longer-term activities to restore and improve facilities, livelihoods, and conditions of affected communities following an emergency.  ontario​
• Redundancy Deliberate duplication of critical systems or resources (power, communications, access routes) to increase reliability in emergencies. macog​
• Residual risk The disaster risk that remains even when effective disaster risk reduction measures are in place, and for which emergency response and recovery ca-pacities must be maintained.
• Resilience Ability of a system, community, or organization to resist, absorb, accommodate, recover from, and adapt to the effects of hazards in a timely and efficient manner. who​
• Response plan Documented collection of procedures and information that is developed, compiled and maintained in readiness for use in an incident (ISO 22300:2018)..
• Retrofitting Reinforcement or upgrading of existing structures to become more resistant and resilient to the damaging effects of hazards.
• Return Period Statistical frequency of an event of given intensity.
• Risk communication Exchange of real-time information and opinions among experts, authorities, and the public about risks and protective actions. who​

S

• Safe refuge / shelter Designated area providing adequate protection from identified weather hazards (e.g., sturdy buildings for wind, shaded and ventilated spaces for heat). who​
• Scenario planning Development of plausible event and impact scenarios (e.g., severe thunderstorm during peak arrival) to test plans and resources. macog​
• Severe Weather Warning (SWW) Official alert of hazardous weather from national meteorological authorities.
• Shelter-in-place Instruction to remain indoors or in current location and take protective actions instead of evacuating, used when outside conditions are more dangerous. who​
• Situation report (SITREP) A routinely produced report that provides current information about an emergency response and immediate and future response actions, an analysis of the impact of the emergency, and related management issues (WHO 2015a)
• Situational awareness Being aware of and attentive to what is happening in a given environment at a particular time, with particular emphasis on the effect of changes in the environment; in effect, knowing how an inci-dent or event is evolving (WHO 2015a)
• Squall line Line of thunderstorms, often along or ahead of a cold front, capable of widespread severe wind gusts and heavy rain. weather​
• Standard Operating Procedure (SOP) Formal, written instructions that describe how to perform routine or emergency tasks consistently and safely. emsics​
• Supercell Highly organized thunderstorm with a persistent rotating updraft (mesocyclone) and high potential for large hail, severe winds, tornadoes, and intense rainfall. sciencenotes​
• Surface Load Capacity Ground bearing capacity relevant for stages, towers, and heavy vehicles on wet soils.
• Structural measures Any physical construction to reduce or avoid possible impacts of hazards, or the application of engineering techniques or technology to achieve hazard resistance and resilience in structures or systems.
• Sudden-on set disaster [A disaster that is] triggered by a hazardous event that emerges quickly or unexpectedly. (UNGA 2016).

T

• Table top exercise (TTX) [A facilitated discussion] that uses a progressive simulated scenario, together with series of script-ed injects, to make participants consider the im-pact of a potential emergency on existing plans, procedures and capacities. The process of sharing information and perceptions about risk.
• Thunderstorm (convective storm) Storm with lightning and thunder, often producing heavy rain, strong gusts, hail, and occasionally tornadoes; driven by instability, moisture, and lifting mechanisms. weather​
• Tornado Violently rotating column of air in contact with the ground and a cloud base (usually a cumulonimbus), capable of extreme localized damage. weather​
• Trigger (decision threshold) Predefined condition or criterion (e.g., lightning within 10 km, wind above 20 m/s) that initiates a specific action such as pausing a show or clearing an area. ipcc​

U V W

• UV Index Standardised scale of UV radiation risk guiding sun-protection measures for attendees and staff.
• Vulnerability Conditions and characteristics (physical, social, economic, environmental) that make a community or system more susceptible to hazard impacts. ipcc​
• Wind chill Index describing how cold it feels due to the combined effect of low temperature and wind, relevant for hypothermia and frostbite risk. timeanddate+1​
• Wind load / structural stability For temporary structures, the combined effect of wind speed, gustiness, and direction on stages, tents, screens, and towers, informing design and shutdown thresholds. ipcc​
• Wind Load Calculation Engineering verification of temporary structures for expected wind actions based on codes.