Tropical Storm Vamei causes widespread floods in Johor

27-28 December 2001

Tropical Storm Vamei, which developed over the South China Sea just southeast of Johor, moved over southern Johor causing strong winds and intense rain which resulted in widespread flooding and a disastrous mudslide. More than 7,000 people from five districts were evacuated when floods hit the state’s low-lying areas.

The storm passed by Johor Bahru at about 11 pm on the night of the 27^th and moved over to the Straits of Melaka the following morning, weakening to a depression as it did so. The depression continued across the southern Straits of Melaka causing strong winds and scattered heavy rain over west Johor, Melaka, Negeri Sembilan and Selangor before making landfall again in Sumatra.

It is rare for storms such as this to occur this near to the Equator. In any case, it is the first time for such an occurrence over this region. The storm began as a low-pressure system over the South China Sea between Sarawak and southern Peninsular but intensified suddenly as a cold surge occurred over the northern Asian continent and weakened just as quickly as it made landfall over southeast Johor.

Rainfall analysis over Johor indicates the heaviest rain occurred in the south. The states of Kelantan, Terengganu and Pahang received heavy rain from the 28^th as the monsoon winds strengthened.

The Meteorological Services Department had monitored the development of the storm from the beginning and had issued Storm Advisories four days in advance and Stage Red Heavy Rain Warnings and Category 3 Strong Wind And Rough Sea Warnings before the storm hit land.The warnings also indicated the expected heavy monsoon rains and strong winds at the same time over Kelantan, Terengganu, Pahang and their coastal waters.

Fig.1: Satellite imagery at 11.00 am 27.12.01 shows Storm Vamei approaching its peak intensity over the South China Sea

before making landfall over southeast Johor and weakening.

Fig.2: Forecast track of Storm Vamei from the Joint Typhoon Warning Center, Guam.

Actual track was to the north of the forecast track over the Straits of Melaka.

Fig.3: Rainfall Analysis shows the heaviest rain occurred over the southern Johor.