06. Develop a trigger system

If not done during the scoping study, you need to decide which hazard you will address with your FbF system. In the EAP you will be asked to provide a brief rationale about the selection of the hazard and when it has caused various humanitarian impacts in the past (Section 3.1 in full EAP). This should include:

• A table that outlines the most severe events of this hazard in the past (see a simple template in the toolbox).
• A written description of what the impacts of this hazard were, who was affected and why, how many people were affected, and what were the main sectors affected

Please refer to chapter 5: Collection risk, early action and impact data to learn more about the data collection of these information.

A trigger system will allow the national society to know when and where to act. Please verify the (s)EAP quality criteria for the trigger and the EAP activation system that are linked in the toolbox below. For FbF, you need to include three components of an operational trigger system:

• A clear trigger statement: When are you going to act based on which forecast and with how much lead time? Please refer to step 10: Develop a trigger statement .
• Intervention map: How will you select the communities in which early actions are implemented? Please refer to step 11: Develop a mechanism that defines the intervention area.
• A trigger monitoring and activation system: How are the forecasts monitored and how are relevant actors alerted? Please refer to chapter 8: Develop EAP activation system.
  

In order to ensure sustainability and alignment of the trigger system, it should ideally be embedded in the national early warning and alert system. At the very least, key actors should be involved in or endorse the trigger development process and its outcomes. Generally, trigger development can be a very technical process, hence cooperation with meteorological services, disaster management authorities, and other experts and institutions that work in the field is necessary. To begin with, you can think about the following aspects that might also shape your advocacy strategy (please refer to chapter 2: Engage your stakeholders).

Mandates
Who has the mandate to issue forecasts and early warning messages? Ensure that you are in line with the official regulations and procedures. In many cases, the meteorological service has the mandate to issue forecasts and issue early warning messages together with disaster management authorities. This is done to avoid confusion, which could happen if there were many groups issuing their own alerts.

Existing initiatives
In many cases, the national meteorological agency is already involved in initiatives around impact-based forecasting or anticipatory action. For example, in Mozambique the government partnered with the World Food Programme (WFP) to develop harmonised drought triggers that are owned by the government. If such early warning mechanisms already exist, you should tap into those to avoid a duplication of work. Perhaps there are existing agreements, MoUs, or trigger activation systems already established.

On the regional level, technical working groups also shape the anticipatory action landscape and thus trigger development. There are several examples in Africa, but also in Latin America and Asia Pacific. Please find an overview of the regional technical working groups here.

Guiding questions to establish a coordination mechanism:

• Who are the key actors issuing forecasts and early warning messages?
• Are there existing initiatives on anticipatory action, such as technical working groups?
• Are there existing agreements or risk information systems that could be used for any of the three parts of the trigger system (trigger statement, intervention selection, and trigger monitoring and activation system)?
• Is there political will within the government to own and maintain the trigger monitoring and activation system?

In order to understand which forecast(s) would be most suitable for your trigger, you need to understand the impact it should forecast. For example, when talking about impacts of cyclones you need to understand what has caused the impact: the winds, the rains or the storm surge? Hence, here you need to review the work that you have done on impact analysis and potential early actions. Please refer to the guidance in chapter 5: Collect risk, early action and impact data and chapter 7: Select early actions regarding the prioritisation of impacts and early actions.

Guiding questions to define hazard variable

• Which impacts were prioritised?
• What has caused the impact?
• What variable can be used to best forecast the prioritised impact?
• How much lead time is needed to implement the early actions? What early actions would be feasible in a given lead time?
• Can this variable be forecasted with the needed lead time?

In order for FbF to allocate funding when a trigger occurs, there must be a certain probability of the event. To safeguard this, it is crucial to select the best-suited forecasts. An analysis of forecast verification, type, reliability, lead times, and sources of data for forecasts should be presented as an inventory, to allow an informed decision about which one to use.

Note that this information does not need to be analysed or calculated by the national society but can be obtained by working with hydro-meteorological services, research institutions, or other experts.

Guiding questions:

• Which agency produces relevant forecasts on national, regional or global level?
• What kind(s) of forecast(s) are produced or how is the forecast produced? Tip: Choices include observed data (e.g. gauged precipitation), statistical forecasts (e.g. extrapolation of an upstream river flow to a downstream location, or an index based on El Niño sea-surface temperatures), and dynamic models (e.g. numerical weather-prediction systems and large-scale hydrological forecasting models). Check the toolbox for more information.
• What outcome is the forecast forecasting? E.g. seasonal total rainfall, flood levels, windspeeds.
• Is the forecast deterministic (showing a single outcome without conveying potential error and uncertainty) or probabilistic (showing the probabilities of one or more discrete outcomes or categories) or issued as an interval (showing an explicit upper and lower limit between which a value is expected to occur)?
• What is the spatial (e.g. what is the level of detail?) and temporal (e.g. how often is the forecast produced in a month?) resolution of the forecast?
• What is the lead time for each forecast, e.g. what is the time between forecast issuance and the shock?
• What regions are covered by the forecasts?
• What is the skill (the quality) of the forecast? How has the skill been assessed (e.g. skill at a specific location, skill at predicting extreme events)?
• Is the forecast available throughout the year? Does the accuracy/skill of the forecast change over time?

The menu of forecast required in the full EAP (section 4.2) requests to provide the following information about the available forecasts (or other relevant early warning and/or monitoring/surveillance systems) and requests to include an explanation about which forecast will be used and why.

• Name of forecast
• Source
• Lead time
• False alarm ratio and missed events
• Number of times the forecast has been issued for this hazard in the last 10 years

You can download a template for the menu of forecast table and a more comprehensive guide on forecast verification or skill analysis in the toolbox below.

Generally, the purpose of the DREF is to fund humanitarian operations by national societies. Hence, the anticipatory pillar of the DREF provides funding for anticipatory action for events of a strength that have caused significant humanitarian impact in the past. In order to demonstrate that the selected hazard has caused humanitarian impacts in the past, information on the previous impacts of the selected hazard in the country should be provided. Please revisit chapter 5: Collect risk, early action and impact data, if you still need to collect impact data.

Guiding questions

• From your impact assessment, which years show humanitarian impact, e.g. because a significant number of people was affected, a significant number of houses destroyed?
• In which years did the National sSociety respond to a hazard, e.g. with a DREF but also other humanitarian funding?
• Which years or events were perceived as disastrous by communities, branches, experts or other stakeholders?
• When was a disaster declared for the selected hazard?

The discussion should result in a decision at what impact level you would want to activate your EAP. For example, you could use reference events stating that you are targeting events like a cyclone with windspeeds greater than a certain amount, which happened in the past in your country.

Note that both EAPs (full and simplified) target the same type of events: those that have caused humanitarian impact in the past. The return period of the event, e.g. of five years can be used as a rule of thumb if there is a lack of data. However, in the EAP this will usually not suffice but you need to show that the suggested magnitude has caused humanitarian impact in the past. Exceptions are cases where only really little data is available.

The full EAP (section 4.3) asks you to do the following:

• explain why you selected a certain magnitude of the event,
• how your impact level was defined,
• how much impact can be expected based on the strength of the event,
• indicate to which return period the selected impact level corresponds

After having defined what magnitude of impact you want to target, you need to link the impact magnitude with the hazard magnitude, e.g. estimating what windspeed would cause houses to be destroyed. Depending on your availability of data (both impact and hazard), you can simply plot historical events on an x-y axis, with the hazard magnitude (e.g. windspeeds) on the x-axis, the impacts (e.g. houses destroyed) on the y-axis. This is called a “hazard-impact curve” and can help you decide at what level of hazard would be important to use as your trigger, because you know it causes substantial impact.

After having analysed the link between impact and hazard magnitude you should be able to determine and justify the level of impact and the corresponding hazard magnitude at which you want to trigger your (s)EAP. Hence, the output of this step should be a threshold of a given forecast variable and its justification. Two more aspects are specifically mentioned in the full EAP criteria:

• Frequency of the threshold being reached: Please show in which years (if the data allows) you would have reached the trigger and what is the frequency of the trigger being reached
• Return period of the event and how the return period was calculated: As mentioned above the return period of five years just serves as a rule of thumb. Still, you are asked to provide the return period of your trigger to avoid that you are triggering your s(EAP) on an annual basis.

For (s)EAPs with a lead time longer than 3 days a stop mechanism is required. A stop mechanism stops the activation of the EAP in case there is a significant change of the forecast, and the threshold is no longer reached or in a different location. Hence, the stop mechanism should include the description of what the national society would do if the forecast changed in strength or location within the last days before the event. That means that also actions need to be planned so that they can be stopped at the point of the stop mechanism.

The trigger statement is a key component of the full and simplified EAP (section 4.1 in the full EAP) and it should exactly state when your EAP will be triggered. The trigger statement should be clearly understood by all stakeholders involved in order to avoid confusion about when a trigger is reached. Please review the trigger data base on the anticipation hub for examples.

A trigger statement typically includes the following ingredients:

• Forecast used and forecast source: The forecast used and forecast source should clearly state which forecast, e.g. a certain rainfall forecast is being used and from what source, e.g. national meteorological service
• Variable: the variable should clearly state which variable of the forecast is being used. Hence, this should be an indicator such as Standardised Precipitation Index (SPI3) or heat index, or water levels at a specific station.
• Threshold of that parameter: Here you put the threshold that you have identified in the previous step. Make sure that your forecast provider is calculating this threshold (e.g. if the forecast is issued in mm of rainfall, but your trigger is in SPI, who will calculate the SPI?).
• Lead time: The lead time defines when the conditions must be met for the anticipatory action to be effective. This helps ensure that interventions are timely and proactive.
• Probability: If available, you should add the probability of the event to happen. For example, the trigger could be a forecasting showing 80% chance or greater of 30mm of rainfall or more.
• Stop mechanism: If your EAP has a stop mechanism it should be mentioned in the trigger statement
• Monitoring system: You need to decide how your forecasts are monitored and who is responsible for this. We will elaborate this further in chapter 8.

A complete trigger statement can look like this:

When the [Source of information] forecasts [Threshold of climate variable OR Threshold of impact] at [Lead time] and with a [measure of probability], actions will be taken. If [stop mechanism] occurs, activities will be paused. This system will be monitored closely by [Monitor] in the following way [System].

Once you receive information about the trigger being reached you should also know in which geographic regions the trigger is reached. You should then know how to prioritize the municipalities and where to intervene. Note that you and the national society will probably not have the capacity to act in all municipalities and support everyone, hence you will need to prioritise in a transparent mechanism. The full EAP criteria state:

There is a map or a clear methodology that will tell the national society where action should be taken based on a combination of vulnerability, exposure, and the forecast, when the EAP is activated based on the trigger model. (Section 4.4 in full EAP template)

Currently there are two main ways to define the intervention area:

Impact based forecasting

In case you have an impact-based forecasting system, it should tell you which locations might be most affected. For example, if your national society has the capacity to act in three municipalities you can select those three municipalities that are forecasted to be most affected.

Indicator-based risk assessment

If you don’t have an impact-based forecast, you can use a regular weather forecast and overlay this with exposure and vulnerability information. This can serve as a proxy to predict where impacts will be highest. The simplest way to do this is to use an indicator-based risk assessment by using the vulnerability and exposure indicators that you have identified in your risk assessment (see chapter 5: collect risk, early action and impact data). This method is used in most EAPs so far.

There is a variety of methodologies to do indicator-based risk assessments. However, the most prominent one is probably the INFORM Risk Index methodology.

There is no defined methodology to derive the intervention map. Hence, if you have another established methodology, please only make sure that you explain it well in the EAP document.