High surf, damaging winds in forecast

State and county agencies Friday prepared for possible flooding of coastal areas from 40- to 60-foot surf and damage from 40 mph winds with gusts of 60 mph — tropical storm force — this weekend.

“Residents and visitors are advised to stay away from streams, drainage ditches and low-lying areas prone to flooding,” said county spokesman Brian Perry on Friday. “People also should not cross fast-flowing or rising water in vehicles or by foot.”

Only highly experienced people should enter the water. Those unfamiliar with the conditions should stay off beaches and beachfront areas, the National Weather Service said.

Based on a briefing with weather service officials, county officials learned that the storm is expected to come in two waves, with the first wave impacting Maui County on Friday night and a second, stronger wave affecting the county tonight and into Sunday morning, Perry said.

Ocean conditions are increasing the likelihood for coastal flooding. Although the swells will come predominantly out of the north-northwest, the size of the surf and wraparound effect will heighten the potential for flooding on the shoreline, he said.

The weather service said surf would rise to 25 to 35 feet today and 40 to 60 feet Sunday along north-facing shores of Molokai and Maui. West-facing shores of Molokai could see 18- to 25-foot waves today with 30- to 40-foot waves Sunday.

A high-surf warning is in effect until 6 a.m. Monday. A deepening low pressure system approaching from the north today will produce “giant disorganized waves” and the potential “for unprecedented coastal flooding and erosion,” the weather service said. Anyone with vulnerable oceanfront property should make preparations for possible flooding.

Coastal evacuations and flooding of roads are possible. Surges and breaking waves near channel entrances to Kahului Harbor are possible, the weather service said. Mariners should exercise caution when using the harbor.

Damaging winds are likely during the storm with downed trees expected islandwide, Perry said. Damaging winds will accelerate over ridge tops, through valleys and in downslope areas of Maui County. There is a potential for hurricane-force winds at higher elevations.

A wind advisory is in effect through 6 p.m. today with a high-wind watch from tonight through late Sunday night, the weather service said. Northwest winds will increase to 20 to 35 mph in some areas, with localized gusts over 50 mph today. Sustained west winds of more than 40 mph with gusts over 60 mph are possible in some areas tonight, Sunday and Sunday night.

Winds this strong can make driving hazardous and result in power outages, said the weather service.

Haleakala National Park expected “extremely high winds” today and Sunday at the summit and may close the district to high-profile vehicles, such as trucks, buses and vans, or to all vehicles with minimal notice, said park spokeswoman Nancy Stimson on Friday.

“Closures will be implemented to protect visitor and employee safety,” she said.

Significant impacts from rainfall are not expected, although flooding remains a possibility, said Perry. The first wave of showers was expected late Friday night and the second, late today and into Sunday.

County officials were making preparations for the winter storm.

Department of Parks and Recreation officials were watching parks and preparing for possible closures if there’s shoreline flooding or dangerous ocean conditions, Perry said.

The Department of Public Works has been assessing available personnel who may need to be called out for possible flooding, landslides, toppled trees and fires. Acting Public Works Director David Goode said preparation work included topping off gas tanks for water trucks, bulldozers and other equipment and making sure drivers will be available for call-outs this weekend.

The department has at least 100 Highways Division personnel countywide to respond to storm-related incidents, Goode said.

The state Department of Land and Natural Resources also was making preparations and issuing advisories.

The Division of Boating and Ocean Recreation advised all boaters with craft in state small boat harbors or using offshore moorings to secure their vessels well in advance of the storm.

The Division of State Parks advised campers and others using facilities along the coastline to move out of harm’s way if necessary.

“This could be a powerful storm, and along with all of our federal, state and county partners, we can’t stress strongly enough, that anyone living or playing along coastlines should pay attention to the latest weather advisories and warnings to be sure they stay safe,” said DLNR Chairwoman Suzanne Case on Friday.

Also, the public was advised to stay out of the water in Lahaina town because of bacterial content exceeding safe levels, the Health Department said Friday. Enterococci was measured at levels of 504 per 100 milliliters during routine beach monitoring.

The safe-level threshold is not more than 130 enterococci per 100 milliliters.

The advisory for the beach is posted because testing for enterococci indicate that potentially harmful microorganisms, such as bacteria, viruses, protozoa or parasites may be present in the water. Swimming at beaches with pollution could be harmful.

The advisory will remain in effect until water sample results no longer exceed the safety threshold.