Tag: Hawaiis

HONOLULU (Island News) — Cold fronts come to Hawaii during the winter, sometimes giving the state much needed rain, other times stormy weather can bring dangerous downpours.

A day after heavy rain hit Windward Oahu, dumping up to eight inches of rain in 24 hours, streams were still swollen with runoff.

But the latest round of rain only caused minor flooding on roads or low lying areas.

“What really matters for flash flooding is how hard it is coming down, and a rainfall rate of two to three or four inches per hour. That brings the water up quickly and the basins can’t handle it so streams, creeks and urban drainage fill up very quickly,” said NWS Science & Operations Officer Robert Ballard.

A video from Waimea Valley on Oahu’s north shore show this effect. Even though there are only light showers at the time, the tranquil trickling falls turn into a gushing geyser as runoff from the mountains came rushing down the stream.

“You don’t want to be near creeks and streams. It doesn’t have to be heavy rain where you are to get flash flooding. The water will come down the mountain and come to you. If you hear thunder or see signs of heavy rain you need to take that seriously,” added Ballard.

Three teenagers on Maui learned that lesson the hard way. The water in Iao Valley turned into a raging torrent trapping them on rocks in the middle of the stream.

They had to be airlifted to safety by Maui Fire Department crews.

When the rain came down on Sunday, so did branches, according to Hawaiian Electric. Those branches then got caught up on power lines and knocked out electricity to tens of thousands of residents.

Kapunahala Elementary was closed even after the rain let up because of a power outage and low water pressure at the school.

Another weather event expected later this week, a kona low passing to the north of us, could cause even more problems.

More flash flooding and not just for the usually wetter windward sides, but also leeward areas. It is also expected to produce some damaging wind.

“Once we get into this event we could see wind gusts of 50, 60 mph from southwest winds as they go up and over the islands and then accelerate as they come down in windward areas,” said Ballard.

While you can’t stop the weather, you can be prepared for it.

Along with staying up to date with the latest forecasts, there are things you can do to get ready for the possibility of severe weather striking.

“If you are in an area where you have had power outages and strong wind events before, you should have non-perishable food, batteries and fuel for your generator or whatever you need,” added Ballard.