It was just another regular Sunday (July 11) afternoon hike for visitors to the Singapore Quarry last weekend - until they witnessed a rockslide where a portion of a cliff broke off and fell into the water below.
Dr Adrian Kuah, who was on an observation deck when the incident happened, took a photograph of the aftermath.
He later uploaded it to Facebook, describing the exposed portion of the cliff face as "where the chunk sheared off, taking with it the trees and shrubs growing on it".
Dr Kuah, 48, director of the Futures Office, National University of Singapore, told The New Paper the incident happened slightly past 4.45pm and that he was alerted to it by a "sudden tearing, almost growling sound".
"I remember being puzzled as to what it was. When we realised what was going on, we were all stunned. I don't think anyone managed to take a video as everything was over in a matter of seconds," he added.
Nestled between the Bukit Timah Nature Reserve and the Dairy Farm Nature Park, the Singapore Quarry is a popular hiking destination among Singaporeans. Dr Kuah said the observation deck last Sunday was packed with families and couples who were also startled by the noise.
An avid nature lover who regularly visits the quarry as he lives in the area, he said this was the first time he witnessed "something of this scale".
He stuck around for 15 minutes after the rockslide but did not notice any more falling rocks.
Responding to queries, the National Parks Board (NParks) said it was aware of the incident and is assessing the condition of the cliff.
"This rockslide incident could have been caused by overburdened soil at that section of the cliff and the continuous rain over the past few days.
"Our preliminary assessments do not show any signs of further soil movement, and we will continue to monitor the stability of the cliff," said Mr Lim Liang Jim, the group director of conservation at NParks.
Access to the viewing platform at the quarry remains open as the cliff is not linked to the viewing deck.
This article was first published in The New Paper. Permission required for reproduction.