Four back-to-back storms over the last three weeks have dumped more rain on parts of the islands than they normally would have seen in months, and drenched Kauai with up to six times more rain than normal for all of March, the National Weather Service said yesterday.

The news comes as forecasters are expecting heavy rains to stick around through the weekend. The weather service also says the possibility of heavy showers will remain in the forecast for all islands for at least 10 more days.

The series of storms to hit the state has caused widespread flooding, rockfalls, sewage spills and road closures from Kauai to the Big Island.

On Tuesday night, a landslide at the Wilson Tunnel on Likelike Highway caused some rocks and mud to fall on the road. Crews will close the town-bound lanes of the tunnel today and tomorrow to prevent further rockfalls.

Homes on the Windward Coast of Oahu sustained as much as $5 million in damage after flash flooding late last month and in early March. Damage totals for other affected areas have not yet been calculated.

A flash-flood watch is in effect for the state through Friday, but could be extended, said Andy Nash, director of operations for the weather service office in Honolulu.

Heavy rains settled over parts of Oahu, Kauai and the Big Island yesterday. Lihue got more than 4.8 inches in the 24-hour period ending at 5:45 p.m. yesterday, while Wailua saw 4.6 inches.

The fourth storm in the series started Monday, forecasters said. Other storms hit from Feb. 19 to 24, March 1 to 3 and March 8 to 10.

For Hanalei, the last three weeks has been the wettest on record since 1907 — two years after meteorologists starting recording rainfall totals for the town, Nash said.

Lihue received 25 inches over the three-week period, compared with just an inch last year. It’s the wettest February and March for Lihue since 1950.

"We’ve just had round after round after round of heavy rain," Nash said. "For Kauai, it’s certainly up there in the record books."

The record-high totals on Kauai come on the heels of an unusually dry 2005 for the island. In December, Mount Waialeale got just 1.67 inches of rain, while Lihue Airport saw just .08 inches — both record lows.

Over the last three weeks, Mount Waialeale has seen more than 106 inches, and Lihue Airport has gotten 28.9 inches.

"Kauai has taken the brunt of the most widespread, excessive rainfall," the weather service said. "Even the normally drier leeward sides have been much wetter than normal."

On Oahu, Poamoho saw the biggest rainfall total over the three-week period, with 63 inches. Wilson Tunnel got 39.1 inches — a far second, but a more than six-fold increase from 2005. Punaluu, Luluku and the Waihee Pump rounded out the top five rainfall totals for Oahu.

Waiakea Uka and Glenwood topped the totals for the Big Island, getting 43.6 inches and 42.9 inches, respectively — up to four times higher than normal. Mountain View saw 37.8 inches, compared with 4 inches last year.

All the storms were created by low pressure systems northwest of the islands, which produce unstable air and tap into tropical moisture, Nash said. A high pressure system to the east of the state has blocked the storms, stopping them from moving quickly across land.

"Storm after storm seems to follow this path," Nash said, adding that there has been little break between the heavy systems — keeping the ground saturated and prone to flooding.