FFG

Flash Flood Guidance (FFG) is defined as the amount of rainfall for a given duration over a small basin needed to create minor flooding (bankfull) conditions at the outlet of the basin.  It is called guidance because it gives index how much rainfall is needed to cause minimal flooding in a basin. Flash Flood Threat is the amount of rainfall of a given duration in excess of the corresponding Flash Flood Guidance value. FFG provides near real time information on the development of warning for flash floods. The initiation of flash floods is forecasted based on satellite image for rainfall estimation, the intense rainfall from rain radar, and rainfall on the saturated soil.

Components of FFG

Oman is exposed to local tsunamis (Makran trench Zone) and distant tsunamis (Sunda trench zone). Other extreme hazards in Oman are tropical cyclones and flash floods. FG consists of data acquisition system, several applications to ingest data of expected rainfall, rainfall, radar integration system, and processing systems to forecast the rainfall and to map the threat area. The system includes GMAP (Gauge-based Mean Areal Precipitation that display rainfall accumulation from rain gauge data and interpolation capabilities. It includes also MMap, Merge Mean Areal Precipitation for images accumulation for visual control assessment.

Products of FFG

The FFG system will produce two primary products which can be used in developing warnings or alerts for flash floods – flash flood guidance and flash flood threat.  The users or forecasters will get the graphical products from radar, satellite, GMAP and MMAP and at the same time forecasters will be able to make decision to send the alert/warning for public, for a certain basin and for certain duration of time.