Residents of Kauai and Niihau face life-threatening conditions, including hurricane-force winds, flash flooding, and coastal inundation. Winds could cause structural damage, uproot trees, and result in widespread power outages. Heavy rainfall may lead to flash flooding, mudslides, and overflowing rivers, particularly in steep terrain. Coastal areas are at risk of significant wave run-up and storm surge, with localized flooding in low-lying areas. The risk of waterspouts and tornadoes exists, especially near Kauai and Niihau, through Monday night.