Significant flash floods left a trail of destruction across parts of Northwestern Trinidad on yesterday afternoon.
Many roadways across from Maraval to east Port- of- Spain were blocked by a muddy mix of water, tree limbs, rocks, and boulders, as well as utility poles and lines.
The flash floods
Copious volumes of water flowed into the Cascade River in St. Ann’s that led into the St. Ann’s River, commonly called the East Dry River, in east Port- of- Spain, as well as the Maraval River further west.
With rainfall falling across elevated terrain, roadways turned into temporary rivers in Maraval, St. Ann’s, and Cascade that damaged numerous vehicles and sent at least two cars into the Cascade River.
Violent rainfall began across Saddle Road, Andalusia, La Seiva, and Maraval shortly after 2,30 pm, with flash flooding occurring within minutes as water seemingly cascaded the steep hillsides onto roadways from out of nowhere.
For those already stuck in traffic along Saddle Road, floodwaters rapidly rose around vehicles.
The torrent from the hills brought tree limbs and large rocks that damaged some cars, sending much scampering for drier land.
As the muddy waters moved further downstream, the boulders and tree limbs caused damage to minor bridges, railings, and nearby properties, particularly in Maraval and St. Ann’s.
Flooding was also reported along Long Circular Road and Upper Bournes Road, St James.
Further east, the water from Cascade and St Ann’s met in the St Ann’s River.
Within minutes, the river over topped flooding roadways adjacent to Piccadilly Street, including Prince,Duncan, Nelson , Queen’s Streets, Mucurapo Road, Ethel Street, Independence Square (South), South Quay, and the Priority Bus Route.
The East Dry River brought a significant amount of debris as far as Broadway at City Gate, causing a nightmare of an afternoon commute for those leaving the Capital. Fortunately, there have been no reports of injury.
Though not as impactful, heavy showers also affected parts of central Trinidad earlier yesterday, with street flooding reported in Couva.
The Ministry of Rural Development and Local Government has activated all municipal corporations across Trinidad to respond.
Minister Kazim Hosein called on corporations to adopt an “all-of-corporation” approach.
According to the ministry, equipment and resources from the various municipal corporations, CEPEP, and the Ministry of Works and Transport have already been mobilized to assist with the clearing of debris and sediment caused by the heavy rainfall.
What happened – A link to climate change?
On Tuesday, three factors came together, which is typical for the wet season. First, high temperatures near the surface of the earth causing moist air to rise. This rising motion was further aided by sea breeze convergence, where light westerly winds collided with prevailing light easterly winds. Lastly, orographic effects, where hilly terrain like the Northern Range funnels moist air upslope into a developing thunderstorm.
What makes this event particularly severe is that winds higher in the atmosphere that move these showers and thunderstorms were also light, meaning any showers or thunderstorms that developed remained stationary with precipitation accumulating in a small area.
Between Carenage and Port- of- Spain, up to 75 millimeters of rainfall was recorded between 2,30 pm and 4.30 pm, and rainfall rates were in excess of 100 millimeters per hour.
This amount of rain within two hours in any area would trigger severe floods, regardless of the terrain. However, climate change may play a role in these extreme rainfall and subsequent flood events.
The T&T Meteorological Service has noted over the last forty years, while overall average rainfall has decreased, intense single-day rainfall events have steadily increased.
In fact, six of the top ten years that had single-day highest rainfall events have occurred since 1990.
From 1980 to present, there have been increases in single-day extreme rainfall days and an increase in three-day maximum rainfall totals.
These latter two rainfall event classifications produce high-impact flood events.