Remnant moisture from post-tropical cyclone Fernanda is forecast to approach the state starting late Sunday, with the highest rainfall totals for Maui County expected to occur between Monday afternoon and Tuesday morning, according to the National Weather Service. Showers are forecast to be brief and primarily focused over windward and mauka areas.
As the storm system approaches, emergency response crews have worked to deploy inlet protection devices at all street-level storm drain catch basins in the Lahaina disaster area, and absorbent booms have been installed by the US Coast Guard at eight storm drain outfalls entering the ocean within the impacted areas of Lahaina town.
Preventative measures help reduce sediment runoff and absorb pollutants prior to impacting marine environments, helping protect Maui’s natural resources.
Even with protective measures in place, runoff from heavy rains could still result in dangerous ocean water quality conditions along shoreline areas between Kāʻanapali and Olowalu Landing. Out of an abundance of caution, beachgoers are advised to remain out of any brown water in those areas.
Landscapes that have been severely impacted by wildfires are also at heightened risk for flooding during periods of heavy rain, as vegetation that would typically absorb rainfall has been burned away, increasing the possibility of flash flooding or mudslides.
Areas that may not ordinarily be considered flood prone can be subject to flooding, including flash flooding, after wildfires. Motorists and bicyclists are also advised to avoid traveling on flooded roads in the Lahaina area, as fire damage and heavy rains could cause roadways to become unstable.
Residents in areas that have been recently impacted by wildfires are asked to be vigilant about rainfall and flood risks resulting from heavy rains.