Downtown Kajang was struck by massive floods turning roads into  fast flowing rivers today after a storm hit the Klang Valley this afternoon.

Videos of the deluge have gone viral on Facebook , including a dramatic rescue of a woman trapped on the roof of a van. [View video here ]

According to the fire and rescue department, the banks of Sungai Langat burst at about 3pm, causing waters to rise about half a meter, subsiding only after three hours.

Flood waters poured into Plaza Metro, a major landmark in Kajang,  flooding the ground floor of the complex and the underground carpark. 

Malaysiakini reader Vikram Janardhan Nagappan reported that cars were being washed away near the Pusrawi Medical Centre. 

"Near Plaza Metro, it is worse... (Even) Rapid KL busses could not move because the current was strong," he said.

Kajang state assemblyperson Lee Kim Sin said this was the worst flood to have hit the town since 1971.

He estimates that floodwater rose up to 1m, affecting three quarters of the town and submerged about 200 cars.

“At one point of time, the whole town was locked out to the outside world,” he told Malaysiakini .

KTMB has since ceased its commuter train service to the town.

Lee said 30 houses in low-lying areas near Sg Kantan were inundated.

He blamed deforestation as the main cause of the incident, although heavy rainfall has partially contributed to the banks of Sg Langat being breached.

“About 200 ha of forest reserve were awarded to a company to plant rubber trees in 2008. Can you imagine, the whole hill was cleared,” he said, pointing the finger at the former BN state government.

He said the Kajang Municipal Council (MPKj) has since widened the Sg Langat tributary, Sg Jelok and erected floodwalls to enhance flood defense, but the effort was inadequate to overcome the effects of deforestation.

At 6pm, floodwaters began to subside, and 200 MPKj staff members were then deployed to the scene for cleaning.

The cleaning work is expected to continue until tomorrow.

The last major flood happened in Kajang in 1971, which saw floodwaters rising to a height of 3m.