A storm that pummeled Oahu with heavy rain, thunder and lightning Monday night knocked out power on Maui this morning, and closed roads on the Big Island as a coldfront made its way down the island chain.

Maui Electric Co. spokeswoman Shayna Decker said that at about 2:50 a.m., roughly 66,500 customers on Maui experienced a power outage after lightning hit the electricalsystem across the island, causing damage to electrical equipment, including downed power lines in various areas. By 8:40 p.m., all but 300 customers were back online.

The Maui Police Department reported an islandwide power outage as early as 3:22 a.m. today, but said police dispatch was still able to receive calls.

Haleakala Highway at the intersection of Hana Highway was also closed early this morning due to flooding, according to police.

On the Big Island, the National Weather Service issued a flash flood warning that expired just before 2 p.m., but not before flooding roads.

Hawaii County police reported at 8:50 a.m. that Wood Valley Road near Pahala in the Kau District was closed due to flooding, as was the Kamehameha Avenue and PauahiStreet intersection later in the morning. Rain gauges along the Kona slopes recorded rainfall rates of 1 to 2 inches per hour.

The state Department of Health issued multiple brown water advisories today for the islands of Maui, Hawaii and the east coast of Kauai due to the heavy rains. The publicis advised to stay out of flood waters and storm water runoff due to possible overflowing cesspools, sewer manholes, pesticides, animal fecal matter and pathogens.

In addition, the department’s Clean Water Branch was notified by Maui County of a wastewater discharge near the Wailuku pump station due to the power outage. The publicwas advised to remain out the waters north of Kahului Harbor from Kanaloa Avenue to Linekona Street until signs have been removed.

A high surf advisory for the north and west facing shores of smaller isles of Niihau, Kauai, Oahu, Molokai and Maui is also in effect until 6 p.m. Wednesday, with surf is expected toreach 10 to 15 feet on Maui County, 12 to 16 feet on Oahu and 15 to 20 feet on Kauai and Niihau. A small craft advisory also remains in effect until 6 p.m.