The Department of Meteorology has reported that more than 100 millimetres of rainfall fell over Colombo within less than an hour last evening, triggering flash floods in several parts of the city.
Director General Ajith Wijemanne said approximately 123 millimetres of rainfall was recorded in Colombo yesterday, with the intense downpour occurring within a very short period.
He warned that similar spells of intense rainfall could occur at certain locations in the southwestern parts of the country over the next few days.
Wijemanne explained that Colombo had previously recorded rainfall levels approaching 140 millimetres per hour, with more than 100 millimetres falling within a short period on such occasions. He also identified blocked or obstructed drainage systems as a contributing factor to the flooding.
Inter-Monsoon Conditions Contributing to Heavy Rainfall
The Director General said Sri Lanka is currently experiencing the Second Inter-Monsoon season, during which convective rainfall is common.
Cloud formations typically develop following sunny conditions in the morning, resulting in heavy showers within 30 minutes to an hour, particularly after 1.00 p.m.
He added that prevailing El Niño conditions and the presence of the Intertropical Convergence Zone (ITCZ) near Sri Lanka are also influencing rainfall patterns.
Changes in wind direction and atmospheric instability in the lower atmosphere are further creating favourable conditions for sudden and intense rainfall.
Wijemanne warned that similar weather conditions could persist over the coming weeks, particularly across the Western, Sabaragamuwa, North Western, Central and Southern Provinces, including the Galle and Matara districts.
Some areas could experience rainfall exceeding 100 millimetres within a very short period.
Colombo Flooding Prompts Emergency Discussions
Heavy rainfall last night inundated several roads and other areas across Colombo, resulting in severe traffic congestion.
In response, representatives of relevant institutions convened this morning to discuss measures to address flooding in the city.
The meeting is currently underway under the leadership of Colombo Mayor Vraie Cally Balthazaar, with representatives from all relevant institutions participating.
