Days with fire danger exceeding a threshold

The index reports the total number of days per year with a critical level of fire danger. Fire danger is based on the Canadian Fire Weather Index (FWI) which is one of the most commonly used fire indices globally. It is based on a numerical rating of the potential frontal fire intensity and combines the rate of fire spread with the amount of fuel being consumed. The calculation of FWI requires several meteorological input variables (see the ETC-CCA Technical Paper for details).
FWI values are classified into several fire danger classes. According to the classification of the European Forest Fire Information System (EFFIS; EC, 2020), FWI values in the range 11.2-21.3, 21.3-38 and 38-50 represent ‘moderate’, ‘high’ and ‘very high’ fire risk, respectively. However, different classifications are being used at national levels. The index presented here shows the annual number of days with high fire danger conditions (defined as daily FWI values above 30 in the underlying CDS dataset).