 Ioke at its record peak intensity west of theHawaiian Islands on August 24 | |
| Meteorological history | |
|---|---|
| Formed | August 20, 2006 |
| Extratropical | September 7, 2006 |
| Dissipated | September 12, 2006 |
| Violent typhoon | |
| 10-minute sustained (JMA) | |
| Highest winds | 195 km/h (120 mph) |
| Lowest pressure | 920hPa (mbar); 27.17 inHg |
| Category 5-equivalent super typhoon | |
| 1-minute sustained (SSHWS/JTWC) | |
| Highest winds | 260 km/h (160 mph) |
| Lowest pressure | 900hPa (mbar); 26.58 inHg |
| Category 5 major hurricane | |
| 1-minute sustained (SSHWS/NWS) | |
| Highest winds | 160 mph (260 km/h) |
| Lowest pressure | 915mbar (hPa); 27.02 inHg |
| Overall effects | |
| Fatalities | None |
| Damage | $88 million (2006USD) |
| Areas affected | Johnston Atoll,Wake Island,Minamitorishima,Kamchatka Peninsula,Alaska |
IBTrACS | |
Part of the2006 Pacific hurricane andtyphoon seasons | |
Hurricane Ioke, also referred to asTyphoon Ioke, was a record-breaking, long-lived and extremely powerfultropical cyclone that traversed the Pacific for 17 days, becoming aCategory 5 hurricane on theSaffir–Simpson scale on three different occasions. It was the most intense hurricane ever recorded in the CentralPacific, as well as the fifth-most intensePacific hurricane on record, tied with 1973'sHurricane Ava. It also generated the mostaccumulated cyclone energy for a single storm, untilCyclone Freddy surpassed its record in 2023. Ioke was the ninthnamed storm, fifth hurricane, and third major hurricane of the active2006 Pacific hurricane season.
The cyclone developed in theIntertropical Convergence Zone on August 20 far to the south ofHawaii. Encountering warm waters, littlewind shear, and well-definedoutflow, Ioke intensified from a tropical depression toCategory 4 status within 48 hours. Late on August 22, it rapidly weakened to Category 2 status before crossing overJohnston Atoll. Two days later, favorable conditions again allowed forrapid strengthening, and Ioke attained Category 5 status on August 25 before crossing theInternational Date Line. As it continued westward, its intensity fluctuated, and on August 31, it passed nearWake Island with winds of 155 mph (250 km/h). Ioke gradually weakened as it turned northwestward and northward, and by September 6, it had transitioned into anextratropical cyclone. The remnants of Ioke accelerated northeastward and ultimately crossed into theBering Sea, and then theGulf of Alaska.
Ioke did not affect any permanently-populated areas in the Central Pacific or Western Pacific basins as a hurricane or a typhoon. A crew of 12 people rode out the hurricane in a hurricane-proof bunker onJohnston Atoll; the crew estimated winds reached over 100 mph (160 km/h), which damaged trees on the island but did not impact the island's bird population. The typhoon left moderate damage onWake Island totaling $88 million (2006 USD, equivalent to $130 million in 2023[1]), including blown off roofs and damaged buildings, though the infrastructure of the island was left intact; all military personnel were evacuated from the island. Later, the extratropical remnants of Ioke produced a severe storm surge along theAlaskan coastline, causingbeach erosion.
Extratropical cyclone, remnant low, tropical disturbance, or monsoon depressionTheIntertropical Convergence Zone (ITCZ) spawned a tropical disturbance with a low-level circulation far to the southeast ofHawaiʻi in the middle of August 2006. Under the influence of a strong westward-movingsubtropical 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 775 mi (1,245 km) south ofHonolulu, Hawaii. At the time, there was noconvection associated with the ITCZ within 10° Longitude.[2] Withwind shear practically non-existent andsea surface temperatures of around 82 °F (28 °C), conditions favored strengthening,[2] and operationally the cyclone was forecast to reach minimal hurricane status within four days before beginning to weaken.[3] The depression attained tropical storm status within six hours of developing.[2] TheCentral Pacific Hurricane Center designated the system with the nameIoke/iːˈoʊkeɪ/,Hawaiian for the nameJoyce.[4] Subsequently, Ioke quickly strengthened, and by late on August 20 the storm developed acentral dense overcast and the beginnings of aneyewall;[5] early on August 21 the storm intensified into a hurricane, just 24 hours after first developing.[2]
Hurricane Ioke steadily deepened as it continued west-northwestward, with better definition of the eye and deepening of the eyewall convection.[6] Near theInternational Date Line afrontal trough turned the hurricane to the northwest, and after a period ofrapid deepening Ioke attained winds of 135 mph (215 km/h) early on August 22 while located about 280 mi (450 km) southeast ofJohnston Atoll. After maintaining Category 4 status on theSaffir-Simpson Hurricane Scale for about 18 hours,[2] southwesterly wind shear slightly disrupted the inner core of the hurricane,[7] and Ioke quickly weakened to winds of about 105 mph (169 km/h). Late on August 22, the hurricane passed about 30 mi (48 km) south of Johnston Atoll,[2] with the northeastern portion of the eyewall crossing the atoll early on August 23.[8] 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 23 mi (37 km) closed eyewall,[9] and on August 25 Ioke attainedCategory 5 status on the Saffir-Simpson Hurricane Scale while located about 970 mi (1,560 km) west-southwest of the Hawaiian Island ofKauaʻi.[2]
After maintaining Category 5 status for about 18 hours,[2] Ioke weakened slightly due to aneyewall replacement cycle.[10] Completing the cycle on August 26,[11] 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.[2] The overall environment remained very favorable for sustainment of the powerful cyclone. Strong upper-level cyclones far to its northwest provided outflow channels and light wind shear, with warm water temperatures along its path.[11] With the conditions, theGeophysical Fluid Dynamics Laboratory hurricane model predicted Ioke to reach winds of 220 mph (350 km/h), with a predicted minimum pressure of 860 mbar (25 inHg).[12] Early on August 27, the pressure dropped to 915 mbar (27.0 inHg), and shortly thereafter Ioke crossed theInternational Date Line, becoming a 160 mph (260 km/h) typhoon.[2]
Unofficially referred as asuper typhoon by theJoint Typhoon Warning Center (JTWC), Ioke remained at the equivalence of a Category 5 hurricane for about 12 hours after crossing the Date Line. It then began a slight weakening trend on August 28,[13] due to increased inflow from the ridge to its north.[14] 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.[13] TheJapan Meteorological Agency (JMA) assessed Ioke as attaining peak 10‑minute sustained winds of 120 mph (195 km/h) on August 30.[15] 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 nearWake Island with winds of about 155 mph (250 km/h).[13]
By September 1, increased wind shear and drier air caused the eye of Ioke to become cloud-filled and elongated,[16] and by September 2 Ioke was undergoing another eyewall replacement cycle.[17] On September 2, Ioke passed about 50 mi (80 km) north ofMinami-Tori-shima with winds of about 125 mph (200 km/h).[18] Gradual weakening continued, and the typhoon steadily shifted its track to the northwest around the subtropical ridge. A deepeningtrough turned Ioke to the north-northwest and north,[19] and the cyclone weakened to a tropical storm a few hundred miles east ofJapan. After accelerating northeastward, the cyclone began losing tropical characteristics, and the JTWC declared Ioke as anextratropical cyclone on September 6.[13] The JMA maintained Ioke as a typhoon until a day later, and maintained Ioke as a tropical cyclone until it was declared extratropical midday on September 6. The extratropical remnants of Ioke were tracked by the JMA until September 7, when it was located near theAleutian Islands ofAlaska.[15] The storm deepened as it approached the Aleutians, and re-developed winds of hurricane-force. The storm entered theBering Sea on September 8, and after turning eastward, crossed the Aleutian Islands and entered theGulf of Alaska. The extratropical remnants of Ioke dissipated nearsoutheastern Alaska on September 12.[20]
Late on August 21, about 24 hours prior to its closest approach, theCentral Pacific Hurricane Center issued ahurricane warning for uninhabited territory ofJohnston Island,[21] due to the uncertainty of whether anyone was on the island.[22] AUnited 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.[23][2][24] 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 110 to 130 mph (175 to 210 km/h). 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.[2][23]
Under the threat of the typhoon for several days, twoC-17 Globemaster IIIairlifters evacuated between 188 and 200 military personnel fromWake Island to Hawaii, the first full-scale evacuation of the island since Typhoon Sarah in1967.[25][26] A buoy just east of the island recorded a pressure of 921.5 mbar (27.21 inHg) as Ioke crossed directly over it.[27] Before the typhoon passed just north of the island, an anemometer recorded hurricane-force winds with a peak wind gust of 100 mph (160 km/h) before the instrument stopped reporting.[28] Sustained winds were estimated to have reached 155 mph (250 km/h), with gusts to 190 mph (310 km/h).[29] The minimum central pressure recorded on the island was 934 mbar at 0906 UTC on August 31.[28] The typhoon was expected to produce astorm surge of 18 ft (5.5 m) and wave heights of 40 ft (12 m) along Wake Island, where the highest point is 20 ft (6.1 m). Additionally, heavy rainfall from the typhoon left buildings flooded, with 2 ft (0.61 m) of standing water found several days after its passage.[30]
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.[30] Communications were downed on the island, with satellite dishes and cables destroyed.[31] Damage to the infrastructure was extensive, though repairable and less than expected.[32] Damage on the island was estimated at $88 million (2006 USD).[33]
On September 1, the Japan Meteorological Agency ordered the temporary evacuation of its staff onMinami-Tori-shima, under threat of the typhoon. The agency expected high waves and winds on the island.[34] Facilities on the island were damaged, although it was repaired and fully operational within three weeks after the storm.[35]
Theextratropical remnant of Ioke produced a storm surge and high surf in excess of 30 ft (9.1 m) along the southwestern coastline ofAlaska, which coincided with theastronomical high tide; the combination led to minor flooding alongBristol Bay andYukon-Kuskokwim Delta.[36] Wind gusts peaked at 84 mph (135 km/h) inUnalaska.[37] The system produced moderate to heavy rainfall across the western portion of Alaska, including daily rainfall records of 1.15 inches (29 mm) atBethel and 0.67 in (17 mm) atKotzebue. Rainfall continued into the southeastern portion of the state, contributing to above-normal rainfall totals nearJuneau.[38] Total damage in Alaska was estimated at $113,000 (2015 USD).[39]
TheUnited States Coast Guard first performed an aerial assessment of damage onWake 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.[30] TheUnited States Navy's combat stores ship, theUSNS San Jose (T-AFS-7), and sixteen membersUnited States Air Force's 36th Contingency Response Group atAndersen AFB, Guam arrived on September 8 and analyzed the stability of the airfield along with assisting in clean-up efforts, and after core tests workers cleared the runway to allow flights onto the territory.[40] On September 13, a group of engineers restored power on the island.[41] About two weeks after the cyclone, several buildings were operational.[32]
Hurricane Ioke became one of only seven hurricanes to reachCategory 5 status on theSaffir-Simpson Hurricane Scale in the Central North Pacific Ocean. The others werePatsy in 1959,Emilia,Gilma, andJohn in 1994, as well asLane andWalaka in 2018. With an estimated minimum central pressure of 915 mbar (27.019 inHg), the cyclone attained the lowest estimated surface pressure for any hurricane within the basin,[2] surpassing the previous minimum set byHurricane Gilma in1994.[42] 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.[2] Additionally, the cyclone remained at the equivalence of asuper typhoon for 174 consecutive hours, which was also a record.[27]
The nameIoke was retired from future use in the central Pacific by theWorld Meteorological Organization following the 2006 season. The nameIopa was chosen as its replacement.[43][44]
This article incorporates text from this source, which is in thepublic domain.
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