Weekly Weather Event -Week of March 8thMarch 12, 2021
Hawaii was hit by intense flooding throughout this week, the worst of which was concentrated on the islands of Oahu and Maui. Rainfall totals tended to be quite localized, with parts of Maui being hit from anywhere from 3 to 19 inches of rain, causing the Kaupakalua dam to overflow and forcing residents to evacuate. By Thursday, the heavy rainfall shifted to the island of Oahu, closing roads and also causing evacuation orders. Flooding was additionally reported on the Big Island and Kauai island, which are on opposite ends of the island chain. As of this writing, the Kauai and Oahu islands are still under a flood advisory.
Just with severe weather, there are different categories the National Weather Service uses to define flooding events. Flood advisories are put in place when there is a potential for life threatening or property damaging events to occur, but it is not expected to reach the level of a flood warning. Flood watches are put in place when conditions are favorable for flooding, meaning that the current weather will likely lead to a flood warning. As is true for severe weather or tornadoes, a flood warning means there is flooding about to happen or is already happening.
Flash flood warnings are put in place when a flash flood is happening or about to occur. Given these events can move incredibly quickly, moving to high ground is extremely important when a flash flood warning is put into place. They can occur without the presence of other flooding or even in areas where there is no rain.