When typhoons plunge into eastern Luzon, the dramatic image of the long, forested spine of the Sierra Madre Mountain Range (SMMR) rising between the sea and inland regions invites a comforting myth.
Many believe this range stands guard, shielding communities from the worst of tropical storms, a story rooted in Ilocano and Tagalog folklore. In legend, Sierra—mother of the land—and her two sons, Iloco and Tagalo, face eastward toward the wind-swept Pacific, promising to protect the land to their west. Yet while poetic, this story does not fully capture the mountain’s role in modern science.
A detailed modeling study published in 2023 by meteorologists Gerry Bagtasa and Bernard Alan Racoma in the Philippine Journal of Science (vol. 152 S1) examined 45 tropical cyclones (TCs) that made landfall across Luzon between 2000 and 2020. Using the Weather Research and Forecasting (WRF) model, the researchers simulated scenarios with and without the Sierra Madre terrain to isolate its effect on wind and rainfall hazards. “Luzon‑passing TCs maintain their intensities at landfall regardless of the frictional effects of the mountain ranges,” they write, showing that the mountains cannot stop storms at the coast.
The study finds that the Sierra Madre does reduce wind exposure for certain zones, with accumulated wind‑field energy (AWE) dropping between roughly 1% and 13%. In the Cagayan Valley in particular, the mountain range’s effect was strong enough for the authors to say that “the SMMR can be considered a barrier for that region.” This means that for some inland communities, the mountain does offer tangible protection, softening wind speeds just enough to make a measurable difference.
Yet while winds may ease, rainfall behaves differently. On the western slopes of the Sierra Madre, including parts of Central Luzon and Metro Manila, moist air forced upward by the terrain leads to orographic lift, increasing rainfall by 23% to 55% in some simulations. Meanwhile, in the Cagayan Valley, rainfall can be reduced when the terrain blocks moisture flow. In practical terms, the mountain may slightly reduce wind speeds but can amplify rainfall, meaning flooding remains a serious threat.
This distinction is critical because, in the Philippines, most typhoon-related damage comes from rainfall, flooding, and landslides—not wind alone. The study warns that assuming the Sierra Madre provides full protection may foster complacency among communities and authorities, leaving people unprepared for the real hazards of tropical cyclones.
The science also deflates a common mental image of a storm hitting an impenetrable wall. Peaks of the Sierra Madre reach 1,500 to 1,900 meters, while a major tropical cyclone towers far higher. Terrain influences surface winds and moisture flows but cannot stop a cyclone in its tracks. In other words, the mountain is a partial buffer, not a fortress.
In the final analysis, yes—the Sierra Madre helps—but no—it cannot be relied upon to protect communities from the full fury of tropical cyclones. Efforts to build resilience must assume that wind, rain, and landslide risks will remain very real, and preparing for these hazards is far more effective than hoping the mountain does the job.
Rather than focusing the conversations on the mountain range “protecting” the people from typhoons, the discourse should shift toward safeguarding the Sierra Madre itself from deforestation, mining, and other human activities that threaten its rich biodiversity.
A healthy mountain is a far more lasting legacy than any temporary shield. Protecting its forests and wildlife ensures that it continues to play a role in moderating hazards while preserving the unique ecosystems that have endured for millennia.
