KUALA LUMPUR: Flash floods caused by clogged drains brought traffic to a crawl in Jalan Pahang while hailstorms hit several parts of the Klang Valley.

The downpour since afternoon forced the Stormwater Management and Road Tunnel (SMART) to be closed at 3pm for flood mitigation operations.

"SMART calls on motorists to be patient. Current information will be given to the media from time to time," the operators said in a statement.

The water level started rising at about 2pm near Bulatan Pahang after the downpour.

A Kuala Lumpur City Hall officer said the floods were slow to subside because of clogged drains.

"If the drains are clogged, chances are our water pumps would also be submerged so no water can be pumped out," he said, adding that no complaint of flooding was received in other parts of Kuala Lumpur.

In Taman Melawati in Ampang, Taman Sri Gombak and Taman Bolton, residents experienced hailstorms.

"I thought someone was throwing stones at my car," said Lin Yee Lai, who was driving on the MRR2 on her way home from Selayang at 2pm when the hailstones struck.

With poor visibility, the 43-year-old social worker stopped her car on the emergency lane and watched in amazement the ice balls hitting her windscreen.

"I have not seen anything like this since my school days," she said.

Another resident, Hameedah Ibrahim, heard loud noises on the roof of her house in Taman Melawati and saw ?ice cubes? on the ground when she came out to investigate.