Record rainfall swamps spots on Big Island in February, including 56 inches at one site

“The Big Island had a very wet February.”

That’s how senior service hydrologist Kevin Kodama with the National Weather Service forecast office in Honolulu summed up last month’s rainfall numbers for the island.

For some, it sounds like an understatement. Mother Nature drenched big portions of the Big island in February for extended periods of time and with deluges that at points led to damaging — and in some cases life-threatening — flooding.

Just three Big Island rain gauges measured less than 100% of their average rainfall for February, with several spots in Kaʻū and on the windward side of the island recording rain totals up to nearly six times greater than average. Records for the highest February rainfall total were broken at Glenwood, Mountain View and Piʻihonua, where rainfall data goes back about 30 years.

Kapāpala Ranch and the Mauna Loa Observatory had their highest February rainfall totals since 1979 and 1982, respectively. Hakalau, Hilo Airport, Pāhoa and Waiākea Uka had their highest February totals since 2008.

The Hilo International Airport gauge had the highest daily rainfall total for the month with 11.13 inches on Feb. 18, a record for that day but still not in its top 10 highest daily totals. The all-time daily record for the gauge stands at 16.87 inches on Feb. 20, 1979.

The 37.95 total inches measured last month at Hilo Airport, 371% of the average of 10.22 inches, was its fifth highest February total. The record of 45.55 inches of rain fell in 1979 at the airport in the nation’s “rainiest city.”

Even with all that rain, the Hilo Airport rain gauge comes in last on the list of Big Island gauges that recorded the top 10 highest rainfall totals last month. The other nine were:

• Honoliʻi Stream: 56.58 inches, 396% of its 14.27-inch average.
• Glenwood: 54:49 inches, 350% of its 15.56-inche average.
• Mountain View: 51.44 inches, 449% of its 11.46-inch average.
• Papa‘ikou Well: 46.01 inches, 348% of its 13.23-inch average.
• Piʻihonua: 45.77 inches, 368% of its 12.44-inch average.
• Waiākea Uka: 43.04 inches, 336% of its 12.81-inch average.
• Saddle Road Quarry: 42.71 inches, 412% of its 10.37-inch average.
• Waiākea Experimental Station: 42.68 inches, 383% of its 11.13-inch average.
• Kulani NWR: 39.01 inches, 524% of its 7.44-inch average.

Other notable rain totals include the 29.24 inches measured by the Keaumo rain gauge just up the road from Glenwood. That’s 554% of the gauge’s 5.28-inch average. The Nene Cabin gauge northwest of Pāhala recorded 26.91 inches, or 509% of its average rainfall for February of 5.29 inches. A separate Kapāpala gauge received 23.10 inches, 460% of its average of 5.02 inches. The Lower Kahuku gauge north of South Point, which averages 4.39 inches for the second month of the year, had 19.38 inches, or 441% of its average.

The rain gauge in Pāhala measured 16.30 inches last month, 331% of its 4.93-inch average, and the Mauna Loa Observatory gauge reported 588% of its average rainfall for February, with 6.11 inches compared to the mean of 1.04 inches.

“Until moving to the east side of the island after 30 years in Kona, I had no idea that this much water could fall from the sky,” said Jay Ess in a March 1 post in the Puna Weather group on Facebook.

“Right??” replied Lisa Kanoe Dowd. “Like, where does it all keep coming from? How does that much water get held in the sky for so long? Wouldn’t it just have to crash down all at once?”

“Welcome To The Jungle,” added Douglas Salinger, using the same words as the title of a 1987 Guns N’ Roses song. “It’s called the rain forest. Get it?”

“Of course I get it. I used to work for Surfline meteorology center,” Ess replied. “I joke a lot.”

The first of two back-to-back Kona Lows moved in Feb. 16, with rainfall intensifying the next morning. In Kaʻū, Highway 11 at Kāwā Flats, Wood Valley Road and Kaʻalāiki Road were closed because of flooding. Several flood prone roads in Hilo and Puna also were closed. The storm also resulted in power outages, school closures, shelter openings and first responders called for two drivers who became trapped in flood waters.

Rainfall again intensified the morning of Feb. 18, with the automated rain gauges at Hilo International Airport, Mountain View and Kapāpala Ranch recording rainfall rates of more than 3 inches per hour. That kept existing road closures in place and resulted in additional closures in Puna.

After three days and producing 15 to 23 inches of rain in south and eastern portions of the Big Island, the first Kona Low dissipated, allowing for a short-lived break Feb. 19 from heavy rains. The second Kona Low developed to the northwest of the state, bringing more rain Feb. 20 to the already soggy slopes of Kaʻū. While rainfall amounts from the second storm were less than the first, the already saturated ground meant more flooding that again closed Highway 11 at Kāwā Flats. The second storm produced another 2 to 4 inches of rain on the island.

Strong trade winds filled in across the islands by Feb. 22 and persisted through the rest of the month, but numerous showers and additional heavy rains at times embedded in the trades kept windward slopes of the Big Island swamped. A low pressure system dropped in east of the state Feb. 26, only to enhance rainfall in eastern and southern portions of the island for the last three days of February and into early March.

The stormy weather also dumped a ton of snow on the summits of Maunakea and Mauna Loa on the Big Island, with reports of more than a foot of the wintry precipitation atop Maunakea.

Despite all that rain that made some ask if Noah had any room left on the Ark, there are places still short of their year-to-date rainfall averages. Gauges in North and South Kohala had mostly below-average totals.

The gauge in Kainaliu south of Kailua-Kona, which reported 3.06 inches in February, or 129% of its 2.38-inch average, is at just a little more than half of its 5.99-inch year-to-date average. The Puhe CS gauge in North Kohala was one of those that didn’t quite make it to 100% of its February average this year, recording 1.04 inches of rain last month, or 95% of its 1.09-inch average. So far for the year, the gauge is at 40% of average, seeing just 1.15 inches through January and February compared to its 2.86-inch average.

The Waimea Plain rain gauge didn’t measure more than 70% of its 3.69-inch rainfall average for the month of February, receiving 2.57 inches last month. By the end of last month, the gauge was at just 37% of its year-to-date average of 8.89 inches, measuring only 3.26 inches so far in 2023.

The Honoliʻi Stream rain gauge north of Hilo had the highest year-to-date total, measuring 60.11 inches, or 192% of average, through the end of February.

To see more rainfall totals from around the Big Island for February, click here. For additional year-to-date totals, click here.

You can also read Kodama’s entire report to see how much rainfall the other islands received in February.