MANILA — Tall buildings in Metro Manila intensified wind gusts during Severe Tropical Storm Kristine, especially in narrow spaces, according to wind engineering expert Joshua Agar from the University of the Philippines’ Institute of Civil Engineering.
Agar explained the “canyon effect,” where wind is funneled between high structures, increasing its intensity. His comments came after a viral video showed someone nearly blown away by strong gusts.
“Meron ka kasing dalawang nakaharang na malaking objects dun sa daloy ng hangin. Ngayon yung hangin saan siya mapupunta? It has to go to these canyons dahil parang somehow nadi-direct siya ‘yung enerhiya ngayon na dala ng hangin,” Agar explained, describing how wind energy accumulates in these urban canyons, creating forceful gusts along the streets.
Agar shared footage of Cubao, Quezon City, where southwest winds were intensified by tall buildings. The southwest wind was redirected through these structures, causing concentrated gusts along the streets.
“’Yung hangin, instead na-divert sila to flow across the streets kaya malalakas ‘yung hangin na naranasan dun sa streets unlike ‘yung portions na perpendicular, wala masyadong malakas na hangin dun,” he noted, contrasting it with perpendicular areas that faced less wind pressure.
He further explained that wind generally follows a single path, but when blocked by a structure, it gets redirected around it. “Halimbawa, galing siya sa southeast, then na-encounter niya ‘yung building… It has to go to the sides, sa gilid.”
When redirected winds collide within the canyon, they intensify, he said, which explains why some roads experience stronger gusts.
Agar added that Manila’s winds are often stronger when typhoons are located north of the city, with the westward winds coming in more forcefully due to fewer obstacles across open waters like Manila Bay.
Topography also plays a role, with areas at higher elevations experiencing amplified wind effects. In sloped areas like Quezon City, wind intensity increases as it moves uphill, making these regions more susceptible to gusts than lower-lying areas like Manila.
“Kapag sloping upwards kasi ‘yung lupa, ‘yung hangin na galing sa baba naman tinutulak kasi ‘yun ng kalupaan… kasalubong niya ngayon ‘yung hangin sa taas… ay makakaranas ng intensification at amplification,” he explained.
To reduce wind impact, Agar recommended considering building design and location. Stronger building materials or designs that convert wind energy into less force can make structures more resilient to high winds. Positioning buildings on flatter terrain, as opposed to elevated areas, also minimizes wind intensity.
“Kung nilagay mo sa flat na terrain, ikukumpara mo sa building na nilagay mo sa tuktok ng bundok, mas malakas ‘yung hangin na mararanasan sa bundok, so very mindful tayo saan natin ilalagay yung building natin,” he advised, urging careful site selection for new developments.
Agar also emphasized the role of surface roughness, stating that vegetation increases wind dissipation, which can locally reduce gust strength.
While structural designs contribute to wind intensity, Agar clarified that natural factors, including topography and wind direction, significantly influence the strength of gusts during typhoons and should be considered in urban planning.