Hurricane Ioke

The Intertropical Convergence Zone (ITCZ) spawned a tropical disturbance with a low-level circulation far to the southeast of Hawaii in the middle of August 2006. Under the influence of a strong westward-moving subtropical ridge to its north, the disturbance tracked nearly due westward, with deep convection in the region increasing and decreasing on a daily basis. It slowly became better organized, and early on August 20 the disturbance developed into Tropical Depression One-C while located about south of Honolulu, Hawaii. At the time, there was no convection associated with the ITCZ within 10° Longitude. With wind shear practically non-existent and sea surface temperatures of around , conditions favored strengthening, The depression attained tropical storm status within six hours of developing. Subsequently, Ioke quickly strengthened, and by late on August 20 the storm developed a central dense overcast and the beginnings of an eyewall; early on August 21 the storm intensified into a hurricane, just 24 hours after first developing. Near the International Date Line a frontal trough turned the hurricane to the northwest, and after a period of rapid deepening Ioke attained winds of early on August 22 while located about southeast of Johnston Atoll. After maintaining Category 4 status on the Saffir-Simpson Hurricane Scale for about 18 hours, and Ioke quickly weakened to winds of about . Late on August 22, the hurricane passed about south of Johnston Atoll, After turning westward later in the day, wind shear began to decrease, allowing a second period of rapid deepening. By August 24 the hurricane maintained a closed eyewall, and on August 25 Ioke attained Category 5 status on the Saffir-Simpson Hurricane Scale while located about west-southwest of the Hawaiian Island of Kauai. Completing the cycle on August 26, the hurricane restrengthened to Category 5 status. The trough to its west tracked further away from the hurricane, allowing the subtropical ridge to build ahead of the hurricane which turned Ioke to the southwest. Early on August 27, the pressure dropped to , and shortly thereafter Ioke crossed the International Date Line, becoming a typhoon. due to increased inflow from the ridge to its north. On August 29, the cyclone turned to the west and west-northwest while tracking around the periphery of the subtropical ridge, and Ioke again reached the equivalence of Category 5 status. Later that day, the typhoon weakened to the equivalent of a Category 4 hurricane for the final time, and on August 31 Ioke passed very near Wake Island with winds of about . and by September 2 Ioke was undergoing another eyewall replacement cycle. On September 2, Ioke passed about north of Minami-Tori-shima with winds of about . Gradual weakening continued, and the typhoon steadily shifted its track to the northwest around the subtropical ridge. A deepening trough turned Ioke to the north-northwest and north, and the cyclone weakened to a tropical storm a few hundred miles east of Japan. After accelerating northeastward, the cyclone began losing tropical characteristics, and the JTWC declared Ioke as an extratropical cyclone on September 6. == Preparations and impact ==

during the passage of Ioke Johnston Atoll Late on August 21, about 24 hours prior to its closest approach, the Central Pacific Hurricane Center issued a hurricane warning for uninhabited territory of Johnston Island, due to the uncertainty of whether anyone was on the island. A United States Air Force vessel and a 12-person crew were on the island, and after securing their ship the crew took shelter in a hurricane-proof concrete bunker. There were no meteorological observations on the island, but the crew estimated tropical storm force winds lasted for about 27 hours with hurricane-force winds lasting six to eight hours; peak wind gusts were estimated at . The crew sustained no injuries, and their ship received only minor damage. Hurricane Ioke, with a portion of its eye crossing the atoll, left an estimated 15% of the palm trees on the island with their tops blown off, with some ironwood trees blown over; the island bird population was unaffected. The hurricane produced rough surf which washed away a portion of a sea wall and an adjacent road. A buoy just east of the island recorded a pressure of as Ioke crossed directly over it. The minimum central pressure recorded on the island was 934 mbar at 0906 UTC on August 31. The typhoon was expected to produce a storm surge of and wave heights of along Wake Island, where the highest point is . Additionally, heavy rainfall from the typhoon left buildings flooded, with of standing water found several days after its passage. The powerful winds of Typhoon Ioke caused extensive damage to the island's power grid, leaving most power lines to buildings and backup generators damaged. The combination of the winds and storm surge flooding damaged 70% of the buildings in the territory, many of which with moderate roof damage. All low-lying areas were described as being covered with sea water or sand, and the territory was left without running water. Damage to the infrastructure was extensive, though repairable and less than expected. Damage on the island was estimated at $88 million (2006 USD). Japan and Alaska , west of Alaska on September 7 On September 1, the Japan Meteorological Agency ordered the temporary evacuation of its staff on Minami-Tori-shima, under threat of the typhoon. The agency expected high waves and winds on the island. Facilities on the island were damaged, although it was repaired and fully operational within three weeks after the storm. The extratropical remnant of Ioke produced a storm surge and high surf in excess of along the southwestern coastline of Alaska, which coincided with the astronomical high tide; the combination led to minor flooding along Bristol Bay and Yukon-Kuskokwim Delta. Wind gusts peaked at in Unalaska. The system produced moderate to heavy rainfall across the western portion of Alaska, including daily rainfall records of 1.15 inches (29 mm) at Bethel and 0.67 in (17 mm) at Kotzebue. Rainfall continued into the southeastern portion of the state, contributing to above-normal rainfall totals near Juneau. Total damage in Alaska was estimated at $113,000 (2015 USD). == Aftermath and records ==

The United States Coast Guard first performed an aerial assessment of damage on Wake Island on September 2, three days after the typhoon struck. The flight indicated an overall damage smaller than expected, and reported a lack of oil spill or hazardous material leak. The U.S. Coast Guard arrived by boat with a team on September 7, with a preliminary damage assessment completed four days later; the team repaired a generator to provide power. On September 13, a group of engineers restored power on the island. About two weeks after the cyclone, several buildings were operational. Ioke maintained at least Category 4 status for 198 consecutive hours, which was the longest continuous time period at that intensity ever observed for any tropical cyclone anywhere on Earth. The name Ioke was retired from future use in the central Pacific by the World Meteorological Organization following the 2006 season. The name Iopa was chosen as its replacement. == See also ==