Central Oahu residents living downstream of the Wahiawa Dam are being told to get ready for heavy rain and possible evacuation, a bad sign for anyone in the flood path.

• The whole state is bracing for heavy rainfall and flooding as the storm moves in.
• People below the Wahiawa Dam face the highest risk and are being urged to plan ahead now.
• The reservoir sits well under its limit for now, with room before it reaches trouble levels.
• Officials have set clear warning marks: one for early concern, a higher one for possible failure, and a top one where the dam could start spilling over.
• Hawaii's emergency agency says knowing your evacuation plan in advance is the key step.

Outlook: Rainfall over the next few days will decide how fast the reservoir climbs and whether evacuations become necessary.