Violent gusts of wind from an early-morning storm downed trees, knocked tiles off roofs and caused fish farms to drift from their moorings yesterday.
The effects were felt from Pasir Panjang to Pulau Ubin, as branches landed on cars, trees toppled and caused jams, and the vicious squalls sent outdoor furniture flying.
Commuting to work in Chinatown from her Pasir Panjang home yesterday morning, lawyer Anamika Bagchi, 30, found the way blocked by fallen trees not once but twice - in South Buona Vista Road, and near Tanglin.
"It took me an hour to get to work instead of the usual 15 minutes. To be safe, I took a completely different route home."
Yesterday's storm caused about 10 cases of obstruction on roads here, the Land Transport Authority said.
Magazine writer Rachel Tan, 26, who lives off Tanglin Road, said: "I woke to a shocking view on my balcony - overturned furniture and tall potted plants that had been knocked over. It looked like a typhoon had stopped by."
The chaos was caused by a Sumatra squall between 2.15am and 3.30am that brought rain and gusty winds to many parts of the island, said the Meteorological Service Singapore.
The highest wind speed recorded during the storm was 103.7kmh, near West Coast Highway. The top speed ever recorded in Singapore was 144.4kmh, on April 25, 1984, it said.
Sumatra squalls are common in the south-west monsoon season, typically lasting from June to September or early October, and are often accompanied by gusts of 40kmh to 80kmh.
"For the next fortnight, we can expect a few days of short-duration afternoon showers with one to two Sumatra squalls," a Meteorological Service Singapore spokesman said.
Yesterday's storm is unlikely to have anything to do with this year's predicted El Nino weather phenomenon, said National University of Singapore weather researcher Winston Chow.
Rather, such strong gusts result from extremely strong pressure changes along the leading edge of the storm as it advances towards Singapore from the west.
"Air from the surface gets thrust upwards, then pushed down rapidly, due to density differences between air parcels in the storm," Mr Chow said.
The damage occurs primarily from these very strong downdrafts, which are seen as short-lived but powerful gusts at the surface.
The National Parks Board said the intense storms resulted in 18 fallen trees, 30 fallen branches and six snapped trunks. "There were no reports of injury, and the obstructions were cleared on notification," said NParks streetscape director Oh Cheow Sheng.
The public can call the agency on 1800-471-7300 to report fallen trees, he added.
Mr Veera Sekaran of landscape firm Greenology suggested that the recent dry spell could have put stress on some tree species and weakened their roots.