The Flood flood probability persistence layer shows where on pixels in the model river network with a minimum upstream area of 50 km² where EFAS forecasts a flood, showing indicating both the flood severity level together with the flood probability for cells with an upstream area greater than 50km2.
The persistence probability map combinesrecurrence and total exceedance probability.
The map exhibits the probabilities of exceeding the 2-year (yellow), 5-year (red), and 20-year (purple)
total (combining all models) exceedance probabilities, averaged from the two most recent forecast runsEFAS return periods. It considers the maximum probability for each
hazardrecurrence level across
all forecastthe complete lead time range (10 days).
ItThis layer is used in the definition of the dynamic reporting points, in a way that no dynamic point is generated below the minimum probability thresholds (50%
/ 30% / 30%).2-year / 40% 5-year/ 40% 20-year).
Figure 1. Example of the Flood probability layer on the forecast June 25 2024 12 UTC.
Note. For an explanation on the computation of total probabilities, see this link.
