Typhoon Utor, known in the Philippines as Typhoon Seniang, swept through the central Philippines in December 2006, exacerbating the damage left behind by previous Philippine typhoon strikes that year. Residual moisture from the tropical cyclone indirectly contributed to extensive flooding in Malaysia. Utor originated from an area of disturbed weather that organized into a tropical depression on December 7 west-southwest of Yap. The cyclone steadily progressed westward while gradually intensifying, reaching tropical storm intensity late on December 7. On December 9 and the ensuing two days, Utor crossed the central Philippines and reached typhoon strength before weakening somewhat upon entry into the South China Sea. Reintensification ensued afterwards, and Utor reached its peak intensity on December 13 with maximum sustained winds of 155 km/h (100 mph) shortly after regaining typhoon strength.[nb 1] However, wind shear and dry air began to take its toll on Utor thereafter, quickly weakening the storm until its dissipation on December 15.
Due to the destruction wrought by Typhoon Durian just weeks prior, preparations began in earnest in the Philippines. Over 91,000 people were evacuated from areas at risk, primarily from Albay. Two major summits to be held in Cebu were postponed as a result of the forecast inclement weather. In addition, recovery efforts for victims of Durian had to be suspended and all domestic flights in the Philippines were cancelled. Utor’s impacts in the central Philippines were extensive, with 30 casualties reported and the damage toll reaching US$15.8 million. Widespread power outages affected the entirety of Eastern Visayas. Numerous ships sunk as a result of rough seas generated by the typhoon, including a ferry carrying 104 passengers and crew. Following the storm, relief agencies began to allocate resources to those affected by the typhoon, in turn also adding to relief efforts for the three Philippine typhoons which preceded Utor. Precautionary efforts also took place in Vietnam, Thailand, and Malaysia, while the Paracel Islands sustained marked damage but no fatalities. Although the storm mostly dissipated in the South China Sea, Utor’s remnant moisture later contributed in part to Peninsular Malaysia‘s worst flood event in recorded history, as copious amounts of precipitation fell over a short, four-day period. Eight people were killed by the floods which were worst in Kota Tinggi and Segamat District.
The predecessor to Typhoon Utor was first noted by the Joint Typhoon Warning Center (JTWC) as a cluster of thunderstorms southeast of Chuuk on December 2.[nb 2] Over the next few days, a center of circulation accompanied by intermittent shower activity began to develop in the presence of favorable conditions. At 00:00 UTC on December 7, the Japan Meteorological Agency (JMA) determined that the disturbance had become sufficiently organized to be considered a tropical depression;[nb 3] at the time the cyclone was centered 175 km (110 mi) west-southwest of Yap. Tracking westward under the influence of a powerful subtropical ridge to its north, the depression strengthened into a tropical storm at 18:00 UTC. In accordance, the storm was given the name Utor; this name had been submitted by the United States and means “squall line“.
Utor’s development following its naming was slow, but quickened as the tropical storm neared the Philippines. The tropical cyclone reached the southeastern coast of Samar by 06:00 UTC on December 9 and began tracking through the central Philippine archipelago over the next two days. Despite its interaction with the nearby islands, Utor continued to strengthen without much impediment and reached typhoon strength in the Visayan Sea at 12:00 UTC that day. Twelve hours later, the typhoon attained an initial peak intensity with maximum sustained winds of 140 km/h (85 mph) and a minimum barometric pressure of 955 mbar (hPa; 28.20 inHg) in the Sibuyan Sea according to the JMA. The JTWC analyzed an intensity of (185 km/h) 115 mph at that time. By 12:00 UTC on December 10, Utor had emerged into the South China Sea.
Although Utor tracked back over water on December 10, the storm began to weaken due to increasing wind shear and dry air from the west. As a result, the JMA downgraded Utor to severe tropical storm intensity upon its emergence into the South China Sea. Despite these hindering conditions, the storm’s improved outflow was sufficient enough to enable redevelopment. At 18:00 UTC on December 11, the JMA once again upgraded the system to typhoon strength southeast of Hainan. Intensification continued until Utor peaked with winds of 155 km/h (100 mph) and a minimum pressure of 945 mbar (hPa; 27.91 inHg) the next day. This strength was held for only twelve hours before Utor’s outflow began to succumb to the wind shear and dry air stemming from the monsoonal flow it had previously suppressed. Traveling in a tight clockwise loop, the typhoon rapidly weakened on December 13; by the following day Utor was a minimal tropical storm. At 06:00 UTC on December 14, the storm degenerated into a tropical depression and continued to execute a small anticyclonic loop before dissipating on December 15.