FLASH Performance and Situational Awareness Methods during Catastrophic Flash Flooding Events

The unglaciated portion of the Upper Mississippi River Valley region experiences a higher rate of flash flooding due to steep terrain, increasing the vulnerability of communities near waterways. Recent extreme rainfall events, coupled with wet soil conditions, have led to catastrophic flash flooding. Warning forecasters at the National Weather Service La Crosse Forecast Office applied Flooded Locations and Simulated Hydrographs (FLASH) data and situational awareness tools to aid in assessing the need for a Flash Flood Emergency.

Overnight heavy rainfall events are typically most problematic to operational forecasting, when incoming reports are less frequent and darkness provides limited visibility to determine the severity of flooding. This necessitates the need for having multiple ways to receive incoming information from emergency responders, emergency management, and storm spotters.

This research will review recent FLASH data performance for high-impact flood events and methods used to maintain situational awareness to gauge the flooding threat and magnitude.