abstract:Typhoon Chanchu (international designation: 0601, JTWC designation: 02W, PAGASA name: Caloy) was early-forming tropical cyclone of the 2006 Pacific typhoon season. Hong Kong Observatory (HKO) estimated that the maximum sustained wind speed near its centre reached 185 km/h, making it the most intense typhoon on HKO's record to enter the South China Sea in May.