Forecasting hazards, averting disasters

2.2   Impact-based forecasting

FbA is most relevant for humanitarian actors if the hazard 

being forecast is likely to have a negative impact on a 

vulnerable population, so where the hazard, vulnerability 

and exposure interact (see Figure 3). Understanding at what 

point an action is relevant, where that action should be 

focused and for whom requires linking the forecast hazard 

to anticipated impacts. In order to prepare for and plan 

responses to forecast hazards, a clear understanding of the 

potential scale, severity and timing of impacts is needed. 

Many agencies have implemented or are in the process 

of developing methods to integrate vulnerability and 

exposure information with hazard forecasts to assess 

likely impact. Four major methods are currently being 

used: the threshold method, the qualitative combination 

method, the impact modelling method and the climate 

sensitivity method (see Table 1).