Officials are still assessing and dealing with damage from the March 13-16 storm, which dumped up to 4 feet of rain on Maui.
Kona storm causes flooding and road collapse across Maui
A powerful Kona storm flooded Maui and other Hawaiian islands, destroying roads and leaving thousands without power.
Just four days after a storm with heavy rain and winds exceeding 160 miles per hour hit Hawaii, the Hawaiian Islands are preparing for the next round, which arrives March 19 and continues through the weekend.
Matthew Foster, a meteorologist with the National Weather Service in Honolulu, said another subtropical cyclone known as the Kona Storm or Kona Depression is forming and is expected to bring more rain and flooding, but it doesn’t have the best winds of previous storms.
The heaviest rain is expected on Oahu, Maui and the Big Island, the National Weather Service reports. “Although this storm may not be as strong as last week’s Kona Depression, the impact on individual regions could vary depending on where the rain bands occur,” the weather service added.
The system is expected to drag moisture into the region the night of March 19 and into the 20th, Foster said. A trough will then move into the region and strengthen on March 20th and 21st.
How do Kona storms occur?
Kona means leeward in Hawaiian, and these subtropical cyclones often form to the west or northwest of the archipelago, considered the leeward side of the islands and usually protected from trade winds and heavy rain.
Cyclones are a winter phenomenon, and some years are worse than others. It is caused by a series of planetary waves moving around the Earth.
Matthew Foster, a meteorologist with the Honolulu Weather Bureau, said the systems appear every year, but they don’t always make landfall in Hawaii. “We see them every year, but it’s not every time they attack us,” Foster said. “We’re a small target in a big ocean. They could be 600 miles to the west or east.”
Wind and rain swept through Hawaii from March 13th to 16th.
Officials are still assessing and dealing with damage from the March 13-16 storm, which dumped up to 4 feet of rain on Maui. According to University of Hawaii professor Stephen Bassinger, hurricane-force wind gusts snapped part of a “high-voltage power transmission line that went over a mountain ridge.”
Hawaii Electric is still reconnecting people, Bassinger said. At least 1,848 customers were without power on the Big Island as of March 18, and nearly 2,400 total across the archipelago, according to USA TODAY’s power outage tracker.
According to Hawaii Civil Beat, the floods washed away roads on the island, eroded away washed away houses, and caused sinkholes and other damage. However, as of March 18, no deaths have been reported.
Widespread winds of 50 to 80 mph were reported across the island, with stronger gusts in some locations.
In the early morning hours of March 14, winds reached 135 mph at Kai’aulu Pu’uwaawa’a on Hawaii Island, and the next morning at the summit of Mauna Kea, winds reached 110 mph. On Maui, winds reached 168 mph in Kula. On Oahu, winds reached 131 mph at Makapu’u Beach and 128 mph at historic Schofield Barracks.
In addition to the winds, Bassinger said the precipitation was also “astronomical.”
How did the mid-March Kona storm compare to previous storms?
Bassinger said a similar but worse Kona system occurred in 2006, killing seven people. The rains began in February and continued for 40 days and 40 nights into March, leading to comparisons in rainfall to the Biblical events involving Noah.
La Niña patterns in the eastern Pacific tend to favor stronger low pressure systems, Bassinger said. The events of 2006 occurred as the La Niña phenomenon was waning. The same was true for the floods in April 2018 and March 2021.
Fortunately, there is at least an end in sight for this event, he said. “I’m confident that within two weeks, this pattern will either change significantly or decrease significantly.”
“You know, March comes in like a lion and goes out like a lamb,” he said, adding that this folklore stems from the biggest change that occurs as the Earth moves toward the vernal equinox.
“We are in a period where the sun is stronger day by day than at any other time of the year,” he said. Day length increases fastest around the vernal equinox, when daily changes in solar radiation peak.
Temperature gradients at different levels in the atmosphere are the main source of energy for these storms, so when the sun begins to warm the cold air, it “steals the lightning” from low pressure systems, he said.
Several stations across the island have broken daily precipitation records, but only one of the three major weather stations, Kahului, has reported record rainfall so far in March.
- Kahului received 16.36 inches of rain, surpassing the previous record of 10.9 inches set in March 1967.
- Hilo received 11.43 inches of rain, but the current record for March is 49.93 inches in 1980.
- Honolulu received 10.1 inches of rain, far below the 1951 monthly record of 20.79 inches.
Could the “Kona Depression” be affected by climate change?
Climate change may affect subtropical cyclones in the future. Rising temperatures could increase the chance of heavy rain, Bassinger said, but so far Hawaii has been spared most of the worst sea-surface warming seen in other regions because ocean currents carry warmer water to other areas.
He said there are “two clear trends in the data” in the state. The islands are becoming increasingly dry, with higher elevations drying out faster than lower elevations. And the state is getting warmer.
Dinah Boyles Pulver, a national correspondent for USA TODAY, writes about violent weather, climate change and other news. Contact dpulver@usatoday.com or @dinahvp on Bluesky or dinahvp.77 on X or Signal.
