Adianto P Simamora, Jakarta – There are no floods in the city for months and then they happen all at once. In Jakarta, when it rains, it does indeed pour.

The rain over the past week alerted people living on the banks of Ciliwung River to the possibility of floods.

So, when the river – which divides the sub-districts of Kampung Pulo, East Jakarta, and Bukit Duri, South Jakarta – burst its banks at 5 a.m. on Friday, they were ready.

Valuables, such as photo albums, electronic appliances and motorcycles, were moved upstairs and residents made their way to shelters at Santa Maria Fatimah school and Attauwabin mosque, both nearby.

"At least five neighborhood units were flooded. In my area, floodwaters in at least 40 houses were two meters deep," a woman who was breast-feeding her child at the shelter, Mariam, told The Jakarta Post.

Mariam said she and other residents were informed by the subdistrict head at 1 a.m. the floodwaters had risen to one-and-a-half meters. "We saved our belongings as there was a two-hour window during which we could carry them upstairs," she said. The floodwaters reached two meters at 10 a.m on Friday.

"Many people are huddled on rooftops or are keeping to the second floor... They won't leave unless the floodwaters reach three meters deep," Mariam said. One hundred Kampung Melayu residents whose homes were flooded are sheltering at the school.

The flood, caused by heavy rain in Bogor, West Java, also inundated housing complexes like Pamalang and Reni in Sawangan district.

Although Kampung Dalang, which is near Jl. MT Haryono, East Jakarta, remains dry residents have stowed away their belongings.

Sirait, 50, said she moved electronic goods, mattresses and clothing upstairs. "Look at my living room, it's empty now... You could play soccer... But I decided to leave the cupboard there because it's too heavy to move," she said.

Her house was badly damaged in last year's floods, when the water in her home was five meters deep. "I just renovated this house. Half of it and our belongings were swept away in the flood last year. Thank God, my family was out of harm's way," the mother of four said.

She said if the waters continued to rise people would evacuate to higher ground near hypermarket Carrefour. "We can't sleep well anymore, three times this week we were on high alert," she said.

Flooding is an annual occurrence in Jakarta. The worst flood in recent history took place in 2002, killing 31 people and forcing 300,000 residents to leave their homes. The most-affected people are those living in low-lying areas along Ciliwung River.

Huge floods in the city are usually caused by heavy rain both in Jakarta and its upper areas – Bogor and Depok – as well as a high tide in the northern sea.

Jakarta has 78 areas that are prone to flooding, most of which are in North Jakarta.

The Meteorology and Geophysics Agency (BMG) said the peak of the rainy season in the capital was expected between January and February.