Kauai, Oahu and Maui spent much of Monday under advisory for flash flooding as thunderstorms buffeted the islands.

Kauai took the brunt of the shower activity, with flooding that prompted the closing of Kuhio Highway in the area of Hanalei Bridge and power failures reported around the island.

Haena and Kee beaches were closed to swimming, the county said in a statement. Also, Grove Farm closed the access road to Mahaulepu because of hazardous conditions.

The American Red Cross opened a shelter at Hanalei Elementary School in Hanalei for residents who were evacuated from their homes due to flooding.

In the 24-hour period ending at 5 p.m. Monday, rain gauges recorded 6.52 inches of rain at Mount Waialeale. Heavy rainfall was also detected at North Wailua Ditch (6.1 inches), Wainiha (4.43) and Kilohana (3.76).

At one point during the day, the South Fork of the Wailua River rose 6 feet in an hour, the National Weather Service said.

On Maui the heaviest rain was recorded over the Upcountry area, with rain falling at a rate of more than 3 inches per hour over drainage systems flowing into Makawao and Pukalani, the weather service said.

Heavy rain also developed over the West Maui Mountains, Ulupalakua and Wailea.

Hawaii island also experienced heavy rain near Waikii, Pohakuloa and Saddle Road at about 1:37 p.m., with rain falling at 1 to 3 inches per hour.

Oahu experienced significantly lighter showers, with the heaviest rainfall recorded at Poamoho (0.87 inch over the 24-hour period ending Monday at 5 p.m.).

Forecasters predict that tradewinds will prevail through the week as a ridge remains to the north of the state. Tropical moisture and atmospheric instability will contribute muggy conditions, passing heavy showers and a slight chance of thunderstorms through today.

Drier, windier conditions are expected to return Wednesday as the ridge strengthens to the north.