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An EFAS Flash Flood Notification is issued when the probability of exceeding a 5 year return period magnitude of the surface runoff index is forecasted to be equal or greater than 30% and the forecasted start of the event is =< 48 hours in a region where there is an EFAS partner. Flash flood notifications are sent to the ERCC.

EFAS Flash flood notifications are issued for administrative regions not for basins.

Criteria:

• Catchment part of CoA (Condition of Access)
• Catchment area is <= 2000 km2
• Probability of 5 year ERIC return period >= 30%
• Lead time of the above criterion being satisfied is <= 48 hours

An EFAS Formal Flood Notification is issued when the probability of exceeding critical flood thresholds are forecasted more than 2 days ahead in a river basin with a minimum upstream area of 2000 km2 where there is EFAS partner. The forecast also must be persistent (see below under criteria) and at least one deterministic forecast must exceed the EFAS 5-year return period. Formal flood notifications are automatically added to the ERCC overview (restricted information) and disseminated to the ERCC and the Civil Protection.

Criteria:

•     Catchment part of CoA (Condition of Access)
•     Catchment area >= 2000 km²
•     Event >= 48 h ahead
•     3 consecutive forecasts with >= 30% exceeding EFAS 5 year return period according to ECMWF ENS or to COSMO-LEPS forecasts
•      At least one of ECMWF or DWD forecast exceeds EFAS 5 year return period.

The EFAS Informal Flood Notification is issued when a probability of exceeding critical flood thresholds are forecasted in a river basin where there is an EFAS partner but the forecasted event does not satisfy the rules of an EFAS Formal Flood Notification, e.g. warning lead time, size of river basin, or location of event. An EFAS Informal Flood Notification can also be issued if EFAS results are not conclusive but one of the multiple forecasts indicates risk of severe flooding. Informal flood notifications are sent to ERCC.

Criteria:

• Any of the criteria for formal flood notification is not met
• Catchment part of CoA (Condition of Access)
• Catchment >= 1000 km²
• Any other doubt