A fierce front barreled over O'ahu, Maui County and the Big Island yesterday, bringing driving rain and wind as strong as 70 mph that knocked out power to tens of thousands, downed utility lines and trees, closed nearly 100 public and private schools statewide and created a traffic nightmare for morning commuters.

"It was like a monstrous hurricane," Mililani resident Marion Poirier said. "It was one of the worst storms here I remember. It was really fierce."

Nineteen public schools on O'ahu, Maui and the Big Island will remain closed today because of electricity, water and other problems.

Forecasters say O'ahu has gotten through the worst of the weather, but residents should expect blustery, rainy conditions through the weekend.

A high wind warning was in effect for Maui and the Big Island through 6 p.m. today. A flash-flood watch was in effect for Maui, Kaho'olawe the Big Island through this afternoon.

The brunt of the massive storm hit O'ahu about 3 a.m. yesterday, shutting down several major thoroughfares, knocking out power to an estimated 45,000 customers, forcing the cancellation of city bus service to the North Shore and Wai'anae Coast, and closing six post offices statewide.

A U.S. Postal Service spokesman said the closures meant no mail delivery for the day to more than 40,000 homes, businesses and post office boxes in Mililani, Hale'iwa, Waialua, Wai'anae, Mililani, Kula and Kualapu'u.

Power outages were widespread, especially on the Leeward Coast and North Shore. As of 10:50 p.m. yesterday, about 8,000 customers still had no power and officials said it would likely not be restored until today.

The outages spurred the closure of 90 public schools on O'ahu, Maui and Moloka'i. At least nine O'ahu private schools were closed. Several businesses also were forced to close for the day.

STORM-RELATED INJURIES

Four storm-related injuries were reported statewide.

On O'ahu, a 20-year-old soldier was injured at Dillingham Air Field when he was struck by a 50-pound tent pole picked up by the wind, while a 40-year-old man fell from his roof in Hau'ula while trying to patch a hole. The soldier was treated and released, while the Hau'ula man is in stable condition at The Queen's Medical Center, officials said.

On Maui, two people were injured when trees fell on their parked vehicles at a Kihei park, officials said. The two were able to walk away from the cars, but were taken to a hospital for treatment.

Officials said the strong, fast-moving storm hit O'ahu's Leeward Coast and North Shore particularly hard. More than 16 utility poles fell onto Farrington Highway in Nanakuli, while North Shore residents woke up to see debris all over their communities.

"We're kind of used to it," Waialua resident Jenny Vierra said yesterday. "We just know to make sure we have emergency kits."

During the morning commute yesterday, drivers battled with lane closures on Pali and Farrington highways and a host of other busy roads. Police also were directing traffic at dozens of major intersections islandwide where power outages had knocked out signals.

And throughout the day, police and firefighters went out to more than 150 calls for fallen trees and utility lines, damaged roofs and minor flooding.

No major structural damage was reported.

MINOR DAMAGE

Officials said though the storm packed a powerful punch, it also was moving relatively quickly, which minimized the chance of major damage.

"We got through it with relatively minor damage, but there were a lot of inconveniences," said John Cummings, city Department of Emergency Management spokesman. "In a way, it was a good field exercise."

The city opened its Emergency Operating Center Tuesday night to coordinate responses to the storm. The center closed yesterday afternoon, though officials were monitoring weather overnight.

Once the winds and rains died down yesterday morning, city crews took to the streets to assess damage and start the cleanup. By about 3 p.m. yesterday, the city had responded to about 100 of the more than 250 calls from residents it had received about damaged or fallen trees or debris.

"We're concentrating at this point on debris removal," said city spokesman Bill Brennan. "They're (crews) going around and kind of prioritizing things based on what's most hazardous."

Laverne Higa, director for the city Department of Facility Maintenance, said hundreds of city workers were helping in the cleanup yesterday, clearing out fallen trees and limbs and clearing drainage ditches.

About 80 Hawaiian Electric Co. workers, plus dozens of contractors, also were out yesterday to repair damaged power lines.

HECO spokesman Darren Pai said most of the outages were caused when debris flew into lines, though dozens of poles also were blown over.

"This has obviously been a major disruption," Pai said.

The weather was caused by a front, which brought the heavy thundershowers, and a low-pressure system that brought high winds.

"During my entire career, which is a 40-year one, it perhaps has happened no more than a handful of times where you had both strong winds and strong rain," said Paul Matsuda, National Weather Service lead forecaster. "The closeness of the low gave us strong winds."

The highest recorded gust islandwide was 70 mph, recorded at Schofield. Marine Corps Base Hawaii at Kane'ohe Bay saw a 58-mph gust yesterday morning, while gusts upward of 40 mph were seen in several spots, including Kahuku, Wai'anae and Honolulu Airport.

The Neighbor Islands also saw strong winds. Moloka'i saw gusts topping at 72 mph, the weather service said, while winds at Kaupo Gap on Maui were gusting at 67 mph. Kaua'i saw gusts at 59 mph.

Reach Mary Vorsino at mvorsino@honoluluadvertiser.com.