Hurricane Lowell slams Hawaii, triggering historic tornado watch and widespread flooding » Yale Climate Connections

by Irene Sans and Bob Henson, Yale Climate Connections
September 8, 2026

Hurricane Lowell delivered a major blow to Hawaii, bringing torrential rain, damaging winds, dangerous surf, widespread flooding, prolonged power outages, and the first tornado watch ever issued for the state.

The storm’s center stayed just offshore, passing west of Kauai and Niihau, but Lowell’s large circulation meant significant impacts spread well beyond the eye. It was another reminder that a hurricane does not need to make landfall to cause serious problems.

Lowell had earlier undergone rapid intensification over the open Pacific, reaching Category 5 strength with maximum sustained winds of 160 mph. It gradually weakened on approach to Hawaii and was a Category 2 hurricane during its closest pass, tracking north-northeast just west of Kauaʻi.

Tropical-storm-force winds extended nearly 200 miles from the center, allowing hazardous conditions to spread across a large part of the state. The National Weather Service Doppler radar in Kauai was knocked out of service during Lowell and remained offline Tuesday morning HST.

Torrential rains caused flash flooding

Heavy rain was one of Lowell’s biggest threats, although Lowell’s weakening and acceleration on Monday night, and the patchy nature of its showers and thunderstorms, helped cut down on the observed amounts. According to the NWS office in Honolulu, rainfall totals of 2 to 6 inches were widespread on Monday night across Kauai and Niihau; localized amounts may have been substantially higher in mountainous areas where rainmaking processes are bolstered. Across the other major islands, overnight totals were less than 2 inches. Several observers for the volunteer CoCoRaHS network reported two-day totals of between 4 and 6 inches on the rain-prone east coast of the Island of Hawaii near and south of Hilo.

The prolonged rainfall triggered widespread flash flooding, swollen streams, mudslide concerns, and flooded roads. Kauai was hit particularly hard as intense rain rates continued for several hours, prompting officials to urge residents to stay off the roads as water levels rose quickly. As of Tuesday morning, several roads in Kauai had been blocked by fallen trees and utility poles, according to the Hawaii Department of Transportation, and crews were working to clear roads of wind- and surf-blown debris.

Damaging winds across the islands

Lowell also brought powerful winds to the western islands. Sustained winds topped 50 mph in parts of Kauai, with gusts reaching 75 to 85 mph in several locations. Even stronger gusts were reported at higher elevations, where the terrain helped accelerate the wind. Tropical-storm-force winds also reached Oʻahu, despite the island being well away from Lowell’s center. Peak winds from Lowell included:

Barking Sands, western Kauai: sustained 51 mph (82 km/h), gusting to 84 mph (135 km/h)
Lihue Airport, southeastern Kauai: sustained 53 mph (85 km/h), gusting to 79 mph (127 km/h)
Honolulu, southeast Oahu (Daniel K. Inouye International Airport): gust to 45 mph (72 km/hr)

Hawaii’s first-ever tornado watch

One of the most impactful aspects of Lowell was the severe weather threat that developed within its outer rainbands. This is a common occurrence across the right-hand side sector of a tropical cyclone, with respect to its forward motion, but rarely does a strong tropical cyclone or hurricane approach Hawaii from the southwest in such a way that the major islands wind up in the forward right-hand quadrant that’s favorable for rotation and tornadoes.

Tornado warnings were issued during the storm, although no confirmed tornado touchdowns had been officially documented as of Monday morning.

The National Weather Service office in Honolulu issued a tornado watch at 4:13 p.m. HST Monday for parts of Kauai and adjacent coastal waters. This was the state’s first-ever tornado watch. The NWS Storm Prediction Center issues hundreds of tornado and severe thunderstorm watches each year, often coordinating with local NWS forecast offices, but SPC’s formal domain extends only to the 48 contiguous U.S. states.

Huge waves and coastal flooding

Lowell also generated massive swells across the central Pacific. Offshore wave heights reached 30 to 50 feet, while storm surge of 1 to 4 feet combined with pounding surf to produce coastal flooding, beach erosion, and wave overwash in low-lying areas. The western islands saw some of the greatest coastal impacts.

Dangerous rip currents and life-threatening surf prompted widespread beach closures, with residents and visitors urged to stay well away from the shoreline. The rip current risk will remain high across the northern islands through early Thursday.

No more U.S. land threats from tropical cyclones for the immediate future

We’re near the peak of hurricane season in the North Pacific and North Atlantic, but none of the several named storms in the North Pacific appear destined to take aim at U.S. shores for the foreseeable future. And with no development expected in the North Atlantic through at least September 15, it now appears virtually certain that we will break the modern record of September 11 for the formation of the first Atlantic hurricane in a given year.

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