“Bridges across the Hanalei and Wailua rivers remain closed either to high water or to debris dams,” the National Weather Service wrote. “Landslides in steep terrain” and “significant property damage” were expected.
Kauai resident Mike Laureta told Hawaii News Now that the flooding along the Wailua River was the worst he had seen in 30 years. “If this was a 50-year flood or a 100-year flood, this is it,” he said.
Rainfall totaled 7.33 inches in Lihue on Saturday, while a nearby station ended up with 5.35 inches. Kapahi picked up 6.64 inches.
The highly localized drenching mainly targeted the eastern end of the island. To the south, Port Allen Airport only wound up with 0.08 inches. The distance between the two sites is only 15 miles.
At higher elevations, the tallies were even more extreme. Aided by altitude, a United States Geological Survey station picked up just under two feet of rain in three days’ time. That same station has received nearly 80 inches this March.
The flooding rains are associated with Kona storms that have swept across the northwestern stretches of the Hawaiian archipelago in recent weeks. Such storms — which derive their name from a word meaning “leeward” — are most common in the winter. Some years may pass without a single storm, while other winters may feature up to four or five, according to the Western Regional Climate Center.
Kona storms are a bit different from typical passing storm systems, boasting considerably more rainfall and a more disheveled frontal structure. Unlike tropical storms and hurricanes that have warm centers, Kona storms are “cold core” systems — but they still possess some subtropical characteristics.
March had already been an active month for wild weather in Kauai. On St. Patrick’s Day, island residents were awakened by the first tornado warning issued for the state since 2008.
That same storm had dropped 16.45 inches of rain on the peaks of Mount Waialeale on March 16, with another 11.5 coming down the next day. Almost an inch of rain was recorded in just 15 minutes’ time during the height of the storm.
In the past two weeks, Kauai has been placed under seven severe thunderstorm warnings. This repeated possibility of damaging winds and hail is unusual in what’s more commonly regarded as a tropical paradise.
The island has also found itself beneath nine flash-flood warnings. Kapahi picked up 9.19 inches of rain on March 16.
Hawaii isn’t typically a hot spot for severe thunderstorms, but it’s no stranger to extreme flooding. In fact, Kauai in particular has been the site for numerous rainfall records in past years. It even holds a nationwide title.
In 2018, 49.69 inches fell within 24 hours on Waipa Gardens, on the northern side of Kauai, from April 14 to 15. The National Weather Service confirmed this record as legitimate. Homes were destroyed and parts of the island were cut off for weeks, according to Honolulu-based KHON News. Mudslides and debris blocked long stretches of the Kuhio Highway.
Later in 2018, a community on the Big Island received 58 inches over the course of several days associated with the remnants of Hurricane Lane. That proved to the be second greatest U.S. rainfall total ever observed from a tropical cyclone. Harvey still holds the top spot.
Jason Samenow contributed to this report.