(BIVN) – Hawaiʻi island is now under a Flood Watch, and the summits of Maunakea and Mauna Loa are under a Winter Storm Warning, as emergency officials brace for heavy rains in the coming days.

Rainfall of up to 20 inches is expected throughout a 72-hour period, the County of Hawaiʻi says. Officials anticipate road closures, particularly in flood-prone areas.

From the National Weather Service:

A kona low will move west and away from the state during the next day or so, while a strong area of high pressure north of the islands shifts off to the east. This will bring a moist convergent southeasterly boundary layer flow with a tap into the deep tropics over the island chain, with unsettled weather beginning to affect the eastern end of the state later today and the remainder of the islands tonight. Periods of heavy rain and even a rumble or two of thunder will be possible through the weekend. The weather pattern appears to change little next week, with convergent southeasterly boundary layer flow continuing to bring periods of wet and unsettled weather to the island chain.

The County says the areas expected to see the most severe impacts are Kaʻū, Puna, and Hilo, including areas along the Hāmākua Coast to Waipiʻo Valley. “Road crews, utilities, Fire, and Police stand ready to address impacts caused by the anticipated weather as they occur to ensure public safety,” a news release stated.

In anticipation of severe weather, Hawaiʻi County Civil Defense says Waipiʻo Valley Road will remain closed through Sunday for everyone except Waipiʻo Valley residents and farmers.

Also, the Hele On Park & Ride in Hilo will relocate from Kamehameha Ave. to Kuawa Street Wednesday night through Monday morning.

“We’re expecting a lot of rain over a condensed period and are asking residents to prepare for that,” said Mayor Mitch Roth. “Rainfall is nothing new to us, but as we look at the impacts we’ve had from similar events over the past couple of years, it’s better to be safe than sorry. We’ve seen the benefits of community preparedness and trust that the community will always do what is in the best interest of each other and our collective safety.”

Forecasters say heavy snow is also expected for the mountains, generally above 12,500 feet. The Winter Storm Warning will be in effect through 6 p.m. Saturday. “Storm total snow accumulations of several feet appear likely during the next few days,” the National Weather Service said.

Hawaiian Electric is also urging customers to prepare for the potential impacts from the approaching Kona Low system. The company says crews are prepared to respond to storm-related outages.

The company offers these tips to help customers prepare for potential extended outages:

• Gather emergency supplies, such as a battery-powered radio, flashlights, lanterns and batteries. Be prepared to monitor communications over emergency broadcast radio stations.
• Store enough water, non-perishable food, medicine and personal hygiene supplies for your family members and pets to last at least 14 days.
• Turn off and unplug all unnecessary electric appliances and equipment during a storm or a power outage. When power comes back and is stable, plug in the equipment one at a time.
• Shut off your electricity at the main breaker or switch if you need to evacuate.
  Consider having a backup generator if you are dependent on an electrically powered life support system. Or, make plans to go to an alternate location where electricity will be available. Be prepared to take your medical equipment and medications with you.
• If your business or residence is equipped with a backup generator, learn how to properly operate the device to avoid causing damage or injury.
• Prepare a list of emergency contacts including phone numbers for insurance agents, vendors, physicians, or any other important individuals.
• If you see a downed power line, assume it is energized and dangerous. Stay away from downed power lines – at least 30 feet or more (at least two car lengths).