Kona Storm Leaves Flooding, Structural Damage

A powerful system called a Kona storm brought flooding rainfall, strong winds, some severe thunderstorms and even mountain summit blizzard conditions to Hawaii in mid-March.

Impacts from the potent low pressure system began to build across Kauai and Oahu on March 12, before expanding to all the islands. Heavy rain and gusty winds lingered across parts of the state until March 15.

(MORE: What Is A Kona Low?)

Flooding Rainfall

The Kona Low dumped rain across the islands, causing widespread flash flooding. Houses were damaged and roads were washed out, making travel hazardous. Storm totals reached over 3 feet in some of the higher elevations with widespread rainfall between 5 and 12 inches.

Daily rainfall records fell across the state as heavy rainfall continued for days.

Honolulu set a daily record on the 13th with 5.51 inches of rain, receiving 8.02 inches throughout the storm's duration.

But an even more impressive rainfall record was broken on March 13. Kahului saw 7.4 inches of rainfall that day, which set a record for the highest daily rainfall in a single day, breaking the previous record of 6.4 inches set on December 20, 2017. They also saw their 3rd wettest day the very next day.

Here are some of the most notable precipitation totals:

• Kula (Maui): 44.37 inches
• Kamehamenui (Maui): 34.59 inches
• Mauna Loa (Big Island): 25.45 inches
• Pali (Big Island): 22.67 inches
• North Wailua Ditch (Kauai): 19.38 inches
• Schofield Barracks (Oahu): 19.27 inches

(MORE: Flooding Damages Buildings, Washes Out Roads In Maui)

Extreme Wind Gusts

Wind gusts exceeded 70 mph on several islands with higher elevations seeing gusts top 100 mph, downing trees and knocking out power. By early morning on March 14, around 125,000 customers were without power throughout the state.

Here are some of the most notable wind gusts:

• Kaiaulu Puu Waawaa (Big Island): 135 mph
• Mauna Kea Summit (Big Island): 110 mph
• Kula (Maui): 108 mph
• Waimea (Kauai): 96 mph
• Makapuu Beach (Oahu): 81 mph
• Kamananui (Oahu): 78 mph
• Honolulu (Oahu): 49 mph

...And Even Snow!

Mauna Kea, a volcano on the Big Island, saw snow at its summit during the Kona storm. Snow paired with gusty winds made for blizzard conditions at the island's highest point.

What Is A Kona Low?

Kona lows are storm systems that set up to the west or northwest of the islands and draw up lots of moisture from the south, creating messy and sometimes dangerous conditions. They can bring widespread heavy rain to the islands with the threat of flash flooding, as well as damaging, gusty winds.

This is a phenomenon that occurs most often in January, although it can happen anytime between October and May.

This is a reversal from typical Hawaii weather.

The trade winds across Hawaii typically blow from the northeast. That means windward areas, generally the northeast sides of the islands, typically see more showers. On the Big Island, Hilo is the best example of this. They average a whopping 120.39 inches of rain a year.

But when a Kona storm moves in, it will bring winds from the southwest or “kona” side (or southwest side) of the islands. It's these storms that soak normally drier locations in the islands, including Honolulu and the Kona coast of the Big Island. Honolulu averages only 16.41 inches of rain a year.