March, traditionally the rainiest month of the year for the windward side of the Big Island, was much wetter than usual.
Most of the rain gauges in East Hawaii recorded wetter than average totals for the month.
And Pahoa set a record for March rainfall, with 30.5 inches, or 210% of its March average of 14.49 inches. That eclipses the old record of 29.68 inches set in 1991.
And while this March was wetter than normal, it still lags behind March 2006 — which drenched the entire state and prompted enterprising vendors to hawk “I survived the Hawaii rains of 2006” T-shirts.
“It was certainly a wet month throughout the state, but 2006 set a pretty high bar,” Kevin Kodama, senior hydrologist for the National Weather Service in Honolulu, said last week. “There was a period the second week in March we had a persistent area of low pressure aloft that kept things unstable.
“Sometimes, these patterns kind of stick around. In extreme cases, such as 2006, it was a month-and-a-half worth of that stuff. In this case, it just stuck around for one or two weeks.”
Hilo International Airport recorded slightly less than 25 inches for the month, more than 11 inches above its normal March.
Upslope of Hilo town it was even wetter. Piihonua logged — perhaps waterlogged is a better word — 38.29 inches. That made it the rainiest populated place on the island last month. Waiakea Uka recorded 33.39 inches, more than 1.5 times the average March rainfall.
Residents of upper Puna also saw their catchment systems refilled by Mother Nature — and then some.
Mountain View tallied 30 inches even for the month, almost a dozen inches more than average, and habitually rainy Glenwood received 31.6 inches, 5 inches more than usual for the third month.
The Hamakua Coast, while not quite as rainy, was wetter than normal, as well, with 17.3 inches in Hakalau and 29.12 inches in Laupahoehoe.
Ka‘u and much of West Hawaii also shared in the bountiful rainfall.
“Kona had pretty decent amounts of rain,” Kodama noted.
Ellison Onizuka Kona International Airport at Keahole, where the sun drenches the tarmac and tourists usually deplane wearing shades, had 3.04 inches. That might not sound like much, but it qualifies as the rainiest month since February 2018 in the first place most Big Island visitors see.
Three of the four official rain gauges in the Kona coffee belt, where summer is the rainy season, logged more than twice their average March rainfall.
Kealakekua was the rainiest spot, with 9.46 inches, followed by Kainaliu, 8.87 inches, and Waiaha, 8.02 inches. The fourth spot, Honaunau, measured 7.26 inches, almost double its March norm.
“That’s the summer numbers,” Kodama said. “I don’t know how that’s going to translate for the summer, but for this time of year it’s certainly wet early for them.”
In Ka‘u, Pahala, Kapapala and Kahuku Ranch, all had more than double their March averages, with 14.91 inches, 19.33 inches and 7.62 inches, respectively.
Even South Point, which was in drought in December, received 6.32 inches.
“Things change very quickly. Especially since mid-January, things switched around for them,” Kodama said.
One spot that didn’t share in the prolific precipitation was Kohala.
Upolu Airport received 3.11 inches, a bit more than half its March average. Kohala Ranch, windswept and usually dry, got more than its norm, but that’s still less than 2 inches. And Waimea town measured less than 4 inches, just half its normal March.
“It’s been so wet on the east side, and even on the west side, that people may not realize that Kohala may be slipping into drought very soon,” Kodama said. “The strong winds are not going to help. Things are going to dry out even faster. And as long as we stay in persistent trade winds, Kohala is not going to get much rain.”
The wet weather extended into part of April, and Kodama thinks the daily deluges many Big Islanders have experienced, as of late, are “going to start trending off.”
“There are a couple of factors,” he said. “One, we’re heading out of the wet season, so we’ll be transitioning into it being a little drier. The other thing is the La Nina is weakening … so it’ll be a more normal kind of rainfall.
“But the big thing is the march of the sun. You can’t stop that.”
Email John Burnett at firstname.lastname@example.org.