It was an extremely wet January for much of Hawaii Island, with numerous gauges recording record rainfall for the first month of year, especially in East Hawaii.
Records for the highest January rainfall totals were broken at Glenwood, Kahua Ranch, Laupahoehoe, Mountain View, Piihonua and Waiakea Uka, according to the monthly rainfall summary released Thursday by the National Weather Service in Honolulu.
“What’s amazing is these records are being broken with just half a month’s rainfall, essentially, because it really didn’t rain that much in the second half,” said Kevin Kodama, senior service hydrologist for the weather service.
Glenwood, a habitually rainy spot in the upper Puna rainforest, recorded 42.65 inches of rain — more than twice its usual January total of 19.45 inches.
Kahua Ranch in the Kohala Mountains received 10.49 inches, almost 1 1/2 times its norm of 7.19 inches.
Laupahoehoe’s 21.39 inches was 7-plus inches above its January average.
Mountain View, in upper Puna, tallied 33.73 inches, 2 1/2 times its monthly norm of 13.54 inches.
Piihonua and Waiakea Uka, Hilo locations upslope from downtown Hilo, recorded 30.78 inches and 34.83 inches, respectively — both totals more than twice their normal January rainfall.
The gauge at Hakalau, about 14 miles north of Hilo, measured an eye-popping 46.09 inches of rain, eight times its January norm and almost three times the 15.89 inches received at Hilo International Airport — and the airport’s total was its highest January total since 2002.
Kodama said Hakalau’s rainfall was the second-highest in any month with records going back to 2004. The only month with more rain in Hakalau was August 2018, when 47.83 inches fall, largely due to Hurricane Lane.
In January, East Hawaii’s rivers and streams became swollen and there were numerous road closures because of flooding, especially in the South Hilo, Puna, and Ka‘u districts.
“You know, the Wailuku River got pretty high. It wasn’t Lane high, but it was still pretty darn high,” Kodama said. “The Wailuku River had the second-largest flow in 30 years.”
Kodama said rainfall last month in Ka‘u “was one of the biggest rain events to affect the area since the record-breaking rainfall event on Nov. 1 and 2, 2000.”
Kapapala Ranch and Pahala both experienced more than twice as much rain in a normal January, with 16.53 inches and 13.27 inches, respectively. Pahala’s total was its rainiest January since 2002. And Kahuku Ranch’s 4.77 inches of rainfall is more than 1 1/2 times its average for the month.
The Kona coffee belt, which experiences its rainy season in the summer, had mostly average rainfall totals.
Kealakekua reported 3.68 inches, just above its norm of 3.64 inches. Waiaha was also just above average at 3.52 inches. Honaunau’s 4.49 inches was 126% of its January norm of 3.57 inches. And Kainaliu tallied 2.41 inches, just 2/3 of its norm of 3.61 inches.
Not all locations shared in the bountiful rainfall, however.
Ellison Onizuka Kona International Airport at Keahole, a customarily arid spot, was even more so than usual, with just 0.61 inches, 25% of normal. Kaloko-Honokohau National Historic Park’s gauge recorded 1.28 inches, 60% of its 2.15 inches January norm. And Puuanahulu, about 20 miles north and upslope of Kailua-Kona, received 1.5 inches of rain, 51% of its normal 2.95 inches.
Kodama predicted a wetter-than-normal rainy season in Hawaii, and he thinks that prediction will hold true.
“We’re still looking for wet conditions in February and March,” he said. “We might catch a little bit of a break over the next few days, but we’ll likely get into some more rain a bit later on. And March, the longer-range (computer) models are still projecting wet weather, so I think it will continue.”
Email John Burnett at jburnett@hawaiitribune-herald.com.