Heavy October rains help with dry conditions in East Hawaii

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October rains were plentiful on the Big Island — but they’ll need to keep up the pace to offset drought conditions.

October rains were plentiful on the Big Island — but they’ll need to keep up the pace to offset drought conditions.

“We’ve been pretty wet,” said Kevin Kodama, a hydrologist with the National Weather Service in Honolulu. “But it takes more than just a little rain — you need follow-up rain.”

Throughout East Hawaii in October, rainfall amounts were heavy, surpassing average totals for the month. Rains were so heavy that the U.S. Drought Monitor dropped East Hawaii from its status of “abnormally dry,” now showing much of the Puna and Hilo districts in mostly normal rainfall territory.

“Although most of the Big Island had a wet month, rainfall totals for 2017 through the end of October remained in the near to below average range at most of the gauge locations due to the severity of previous dryness, especially over the summer,” according to the NWS Precipitation Summary, which was prepared by Kodama.

The rain gauge at Kawainui Stream recorded the highest yearly amount, to date, of 117.57 inches, which the report said is 103 percent of average.

The NWS report showed total rainfalls of:

• 23.36 inches at Glenwood (135 percent of average, which is 17.25 inches).

• 22.87 inches at the Papaikou well (145 percent of average, which is 15.77 inches).

• 19.35 inches at Saddle Quarry (181 percent of average, which is 10.72 inches).

• 17.19 inches at Hilo International Airport (176 percent of average, which is 9.77 inches).

• 16.83 inches in Mountain View (128 percent of average, which is 13.19 inches).

• 11.67 inches in Pahoa (100 percent of average, which is 11.62 inches).

• 8.63 inches at Pahala (163 percent of average, which is 5.29 inches)

• 2.99 inches at South Point (122 percent of average, which is 2.45 inches).

• 2.96 inches at Honokaa (57 percent of average, which is 5.2 inches).

• 2.84 inches at Ellison Onizuka Kona International Airport (212 percent of average, which is 1.34 inches)

• 2.56 inches at Waikoloa (298 percent of average, which is 0.86 inches).

“We’re still in a ‘wait-and-see’ mode as far as drought improvement,” Kodama said.

However, the Drought Monitor moved much of the Hamakua Coast into “abnormally dry” from “moderate drought” and even called the area along the coastline of the Hamakua Coast normal for rainfall as of Oct. 31.

South Point, for example, remains at 42 percent of its average rainfall for the year, Hilo 75 percent, Glenwood 51 percent, Pahoa 60 percent and Kona 64 percent.

Kodama cautioned that soil moisture takes time to replenish and noted much of the October precipitation came from heavy rains on a single day, Oct. 24, for East Hawaii. Much of that ran off into the ocean and didn’t soak in, he said.

It will be essential, Kodama said, for rains to continue above normal to counteract the drought conditions. Otherwise, he said, agricultural drought will continue.

Farmers, he said, are “going to need more.”

Email Jeff Hansel at jhansel@hawaiitribune-herald.com.