Hail, flash floods, fallen trees reported in Yishun after thunderstorm

LOW YOUJIN Today Online 30 Jan 18;

SINGAPORE – A thunderstorm on Tuesday (Jan 30) afternoon not only flooded roads, but rained hail and toppled several trees in the northeastern part of the island.

PUB said in a statement late Tuesday night that the flash floods, which ocurred at 5.17pm, were caused by "overland flow from the storm (which) exceeded the capacity of the roadside drains".

The flood subsided around 30 minutes later at 5.45pm.

Earlier in the day, the agency had issued a flood alert for Seletar North Link at around 5.30pm, advising motorists to avoid the area as both lanes of the two-lane stretch was flooded by heavy rain.

According to the PUB, Seletar North Link had experienced a similar flash flood last December.

They agency added that it is in the process of constructing two temporary drains in the area to alleviate flooding. "One such drain will be completed shortly in mid February. The other should be done by May 2018. More permanent drainage is planned in tandem with upcoming developments in the area," it said.

Nearby along Yishun Avenue 1, footage emerged showing several trees lying strewn across the road.

The footage, which was uploaded onto Facebook by Mr Faizal Fila with a caption advising drivers to avoid Seletar Dam, showed large tree branches that appeared to have been snapped off.

The 38-year-old taxi driver told TODAY he was driving home through the affected stretch with his wife at 4.45pm when the video was taken.

"It started at the Seletar West Link CTE exit," said Mr Faizal. He said some of the fallen trees were uprooted, while others had snapped into half. He added that the trail of tree debris went all the way to Yishun Avenue 1 and to Avenue 11.

"Even the Yishun Avenue signboard was smashed to the ground," he said.

Mr Faizal described visibility as being "extremely poor, even when driving really slowly". He added that he did not notice any vehicles that had been damaged by the fallen debris.

Tuesday's storm had also caused collateral damage at a farm at Bah Soon Pah Road.

Ms Ore Huiying shared on her Facebook page damage caused by the storm at Oh Farms. Photos showed broken hydroponic sets littering a portion of the farm, with protective nets and metal frames blown out of place.

The 36-year-old freelance photographer, who helps out at the family farm, told TODAY that strong gusts of wind had also blown off one of the zinc roof structures at the farm.

"It lasted very briefly, but the damages caused were the most serious we've ever seen since operating the farm!" she said.

According to Ms Ore, a neighbouring farm was not spared as well. The strong winds had toppled some of its wooden structures and sent pieces of broken wood flying over to her side.

“Everyone was scrambling for shelter,” she said.

While no one was injured, she estimates that the damage caused by the storm would put production at the hydroponics farm on hold for at least a week.

Social media users also reported witnessing hail during the storm. Footage from videos showed ice pellets the size of grapes falling onto grass patches at a nearby golf course and the balcony of a condominium.

TODAY has reached out to the National Environment Agency (NEA) for comments

According to a description on the NEA website, hailstones are quite rare in the tropics because they usually melt as they fall from the clouds, before reaching the ground. On average, public sightings of hailstones in Singapore occur every one to two years.

The last time Singapore experienced hail was in October 2014.

Elsewhere, other social media users had uploaded their experience commuting through Tuesday's storm. Twitter user The Snapped Fork said she was stuck in traffic on the way from Yishun to Yio Chu Kang.

She wrote that there were more than "20 trees over the road, thick traffic, snapped road barriers, bent signage."

A worker who was clearing the road of fallen trees told TODAY that at least 50 trees had fallen along Seletar North during the storm.

Last week, flash floods were also reported in the Western and Central parts of Singapore, after an afternoon of heavy rain on Wednesday (Jan 24).

The floods were reported at Jalan Boon Lay/International Road, Craig Road and Outram Road.

The PUB says it expects the ongoing Northeast Monsoon season to continue till March.

Thunder, lightning - and hailstones as well
Lydia Lam Straits Times 31 Jan 18;

Stormy weather led to downpours across the island yesterday, causing flash floods in Seletar, felling trees and even raining hailstones.

Some readers reported seeing the tiny balls of ice falling with the rain around 4.30pm.

Ms Junawati Ashak told The Straits Times that it "rained ice" at Seletar Airport at around 4.30pm.

The 45-year-old receptionist at Jet Aviation Singapore said she was in the lobby when she saw the sky darkening outside.

"It rained very heavily and there was a storm with very strong wind. Then the rain came down with ice."

Another reader, who gave her name only as Madam Lee M.L., said she was in her Yishun home at about 4.45pm when she heard a clattering sound.

"The rain came quite suddenly, there was very loud thunder and lightning as well," said the 47-year-old who lives on the fourth floor of a condominium. "When I looked out, I saw some white cubes hitting the glass door of the balcony. I thought they looked like ice cubes."

Madam Lee said there were about five hailstones the size of 5-and 10-cent coins. "It's so amazing to see this on my balcony. I've seen snow before but not hail."

Hail is rare in Singapore but not unheard of. In 2014, hailstones were reportedly seen in Turf Club Road during a heavy downpour. In 2013, a rare hailstorm uprooted trees and disrupted traffic.

The last reported incidence of hail before that was in 2009.

According to the National Environment Agency's website, hail is produced only by cumulonimbus or thunderstorm clouds.

Yesterday's heavy rain caused flash floods on both lanes of Seletar North Link Road at about 5.15pm. The floods subsided about half an hour later.

PUB said in a statement yesterday that it is in the process of constructing two temporary drains in the area to alleviate flooding.

The first drain will be completed in mid-February, while the other is slated for completion by May. More permanent drainage solutions are being planned along with upcoming developments in the area.

The stormy weather also felled a few trees in Yishun and Yio Chu Kang yesterday. At 5.10pm, the Yio Chu Kang Road exit from the Tampines Expressway to the Seletar Expressway was closed due to a tree that blocked the road.

More than 200 incidents of fallen small trees, snapped branches in Tuesday's storms: NParks
Channel NewsAsia 31 Jan 18;

SINGAPORE: There were more than 200 reported incidents of small trees falling and snapped branches after Tuesday's heavy rain and thunderstorms, said the National Parks Board (NParks) on Wednesday (Jan 31).

In an email to Channel NewsAsia, group director of Streetscape, NParks, Mr Oh Cheow Sheng said that Tuesday's event was an example of "extreme storms" in recent years, which consisted of strong winds up to 70km/h or more coupled with heavy rains.

The reported "intense rain and strong winds" during the late afternoon were observed in the north and northeastern parts of Singapore such as Yishun, Sembawang, Seletar, Mandai and Gambas, he said.

"By late evening, NParks had received reports of more than 200 tree incidents comprising mainly small trees and snapped branches, most of which were cleared by 8pm yesterday."

Mr Oh added that NParks staff were on the ground on Wednesday morning to inspect trees in the affected areas and clear remaining debris.

This is not the first time that intense weather events have damaged trees in Singapore. In 2011, 10,000 forest trees were lost at the Mandai area while in 2012 around 100 trees fell in a wooded area at Changi Beach Park.

To prepare for such weather events, NParks has replaced storm-vulnerable trees and carried out targeted pruning and crown reduction prior to the monsoon season, said Mr Oh.

He added that NParks has had in place a "comprehensive tree management programme" since the early 2000s.

Further measures were also implemented in May 2016 to refine crown reduction and pruning processes, said Mr Oh, adding that that these were carried out prior to periods of "more severe weather conditions".

Regular inspection and pruning are key components of NParks’ tree management regime, said Mr Oh. These are based on the tree care guidelines of the International Society of Arboriculture.

"During inspections, NParks’ certified arborists assess the condition of each tree based on their location and site factors," he said.

"Where necessary, diagnostic equipment is used to ascertain the trees’ internal conditions. The frequency of tree inspection and pruning varies according to location, species, age and tree condition."

Mr Oh added that NParks is currently developing modelling techniques to "better understand" the behaviour of trees under varying environmental conditions.

Source: CNA/ad