Heavy rain swamped Oahu on Thursday, sending water flowing over Kamehameha Highway on the North Shore and prompting officials to warn residents across the island to move to higher ground. Emergency management reported at 10:21 a.m. that water was flowing over portions of Kamehameha Highway between Turtle Bay and Sharks Cove, making passage through the area dangerous.
The City of Honolulu
, posting under the handle HonoluluGov as official information from the City and County of Honolulu, retweeted an Oahu Department of Emergency Management alert warning that dangerous flash flooding was happening or about to happen. The alert urged people in affected areas to move to higher ground and avoid flooded areas and roads. Separately, ponding was reported on Kamehameha Highway in Haleiwa near Velzyland Beach, according to the
Honolulu Star-Advertiser
.
Rainfall rates during the event ranged from a half-inch to 2 inches an hour, the Star-Advertiser reported. The National Weather Service in Honolulu issued a Flash Flood Warning for the island, and defconlevel.com reported the warning ran through 1:15 p.m. HST, a timeframe the Star-Advertiser's report also cited. Hawaii News Now, however, reported the warning extended until 4:15 p.m. Thursday — the two outlets differ on exactly when the warning was set to expire.
Flash Flooding Threat Covered the Entire Island
The warning named heavy rain as the cause of the flash flooding and flagged potential impacts to small creeks and streams, urban areas, highways, streets, underpasses and low-lying areas, per the defconlevel.com posting of the alert. It specified that the entire island of Oahu could see flash flooding, not just the North Shore communities already reporting water on the roadway. Forecasters indicated flash flooding was either already underway or expected to begin shortly, with additional heavier showers expected over Oahu in the following hours, especially across the western half of the island, the same posting noted.
Hawaii News Now reported that flood-prone roads and other low-lying areas could close because of elevated runoff and overflowing streams, and warned that urban areas could see significant flooding and property damage from rapid runoff. The station's First Alert Weather Day coverage also noted that heavy showers and isolated thunderstorms were expected to continue into the afternoon as tropical moisture moved northward over the state.
More Rain Possible Into the Weekend
Pockets of heavy showers may continue Thursday night into early Friday night, especially over leeward zones, according to the same Hawaii News Now report. A band of heavy rain and thunderstorms was approaching Oahu Thursday morning, bringing the potential for flash flooding through the afternoon, KHON2 reported, tying the activity to tropical moisture continuing to move north toward the islands.
Not every part of the state faced the same threat. KHON2 reported that the Flood Watch was canceled for Kauai as drier air moved in and shower activity decreased there. Oahu residents and visitors, meanwhile, were urged to steer clear of flood-prone areas, roads, streams and drainage channels while the warning remained active.
