Weather agency warns of major floods and storms

JAKARTA (JP): The national weather agency warned yesterday of even bigger floods hitting Jakarta and other cities in Java in the coming weeks because of heavy rainfalls and tropical storms.

The floods that hit parts of Jakarta on Jan. 13 and Jan. 14 were caused by rainfalls exceeding 100 millimeters, in some parts even reaching 250 mm, the Meteorology and Geophysics Agency said.

"Considering that the rainy season continues until March, Jakarta must anticipate and be on the alert should heavy rain fall within a short period of time (hours) simultaneously in Puncak-Bogor and Jakarta.

"It is feared this condition will lead to even more devastating inundation and floods, and could be disruptive to the activities of people in Jakarta," the agency said.

The floods in Jakarta early this month were somewhat tame because it did not rain as much in the Puncak-Bogor areas, it added.

Because most of the rivers that pass through Jakarta originate in Puncak-Bogor, an exceptionally heavy rainfall in these areas often causes flash floods in the capital city.

Jakarta saw the worst floods in history last year when it rained heavily both in the city and in the Puncak-Bogor area.

The meteorology agency said that the cumulative rainfall in the period between Jan. 11 and Jan. 20 this year reached 207 mm in Central Jakarta and 251 mm in South Jakarta.

The agency also noted exceptionally heavy rainfall in other cities in Indonesia in recent weeks, such as Semarang (160 mm), Manado (102 mm), Ujungpandang (103 mm), Merauke (146 mm), Denpasar (147 mm), and Sanglah (155 mm).

Every millimeter of rain equals one liter of water in a one square meter area. This means that 100 mm of rain in one square kilometer brings in 100 million liters or 100,000 cubic meters of water. After discounting 5 mm (or 5 million liters) for evaporation, there would still be 85 million to 95 million liters of water left.

The meteorology agency also warned of more tropical storms ahead, this time widespread to other parts of Indonesia in the final week of January.

Recalling a tropical rainstorm that hit the southern part of Java island in 1993, the agency concluded that there is a possibility that this will happen again in the coming week.

This could be disruptive to shipping services with waves reaching two meters or more in height.

Rough seas last month severely disrupted ferry services between Jakarta and Sumatra.

The agency has recorded several windstorms in various parts of Indonesia since Jan. 22. A windstorm in Kalianget, Central Java, reached 40 knots, in Tanjung Selor it reached 55 knots.

It also recorded rainfall exceeding 50 mm in Pacitan (92 mm), Ruteng (78 mm), Larantuka (63 mm), Baucau (57 mm) and Timika (56 mm). (emb)