Oahu and Kauai were bracing for more rain and thunderstorms today, even as emergency crews and residents continue to deal with the aftermath of two days of heavy showers on Friday and Saturday.

A flash-flood watch for all islands was extended through 6 a.m. today. The National Weather Service said the risk for flooding would be greatest along windward slopes and in low-lying areas and places with poor drainage, but could occur anywhere the ground is saturated.

During the 24-hour period ending at 3:45 p.m. Saturday, the heaviest showers on Oahu were detected in Niu Valley, where rain gauges recorded 5.59 inches of rain. Other areas experiencing heavy rainfall included Maunawili (5.42 inches), Lyon Arboretum in Manoa (5.09) and Waimanalo (5.02).

The inclement weather kept Honolulu Fire Department personnel and other first-responders busy during the height of the showers between Friday evening and Saturday morning. According to HFD, firefighters responded to 32 water evacuations; six vehicles stalled in flood waters; three emergencies involving electrical hazards, downed power lines or arcing wires; and one blown roof. The highest volume of reported emergencies came from Aina Haina, where firefighters responded to some 20 such calls.

Department of Transportation crews spent Saturday clearing mud and debris from Kalanianaole Highway, which was closed from Aina Haina to Makapuu Friday evening due to flooding. Only one lane was open in both directions at Kalanianaole and Halemaumau Street in Niu Valley and westbound traffic was backed up into Hawaii Kai through the morning and early afternoon.

The highway was finally reopened in both directions around 2:44 p.m.

Kauai bore the worst of the storm activity on Friday and Saturday.

During the same 24-hour period ending at 3:45 p.m. Saturday, rain gauges recorded 11.77 inches of rain in Wainiha and 9.72 inches in Kilohana.

The county spent much of Saturday under a flood advisory as weather radar detected heavy showers falling at a rate of 1 to 2 inches per hour across the southern, interior and northern areas of the island.

The American Red Cross opened a shelter at Hanalei Elementary on Saturday for residents affected by flash flooding and the closure of the road to Hanalei. Kuhio Highway remained closed in the vicinity of Haena Beach Park and the Dry Cave due to rushing waters.

A landslide at around 1:50 p.m. Saturday blocked both lanes of Kuhio Highway in an area about a half-mile north of Waikoko, according to county officials.

The heaviest showers on Hawaii island were detected upslope of Hilo and along the Kohala Mountains, the weather service reported.

The low-pressure system producing the volatile weather is expected to slowly move away from the islands Monday and Tuesday, with breezy trade winds and high clouds continuing through much of the week.