Does the Sierra Madre Really Weaken Typhoons? Filipinos Claim It Protected the Country from Uwan — But Storm Chaser Josh Morgerman Disagrees

Every time a typhoon barrels towards Luzon island in the Philippines—like Typhoon Uwan, known internationally as Fung-wong—many Filipinos turn to a familiar source of hope: the Sierra Madre. Stretching along Luzon's eastern spine, the vast mountain range is often hailed as the 'backbone of Luzon' and its 'first line of defence' against storms.

As it faced its 21st storm this year, the Philippines once again placed its faith in the Sierra Madre's supposed protective powers. But does science back up the sentiment? Storm chaser Josh Morgerman says no. Here's what the data really shows about the so-called 'typhoon barrier'.

The Sierra Madre: The Backbone of Luzon

Rising to 6,283 feet and stretching roughly 335 miles along Luzon's eastern coast—from Cagayan in the north to Quezon in the south—the Sierra Madre spans ten provinces and stands as the Philippines' longest and most ecologically vital mountain range.

Often called the 'backbone of Luzon', it forms a natural buffer between the Pacific Ocean and the country's most densely populated regions.

The mountain range holds around 40 per cent of the nation's remaining forest cover and shelters extraordinary biodiversity, with more than 3,500 plant species—58 per cent of which are endemic. Covering approximately 1.4 million hectares, it also serves as a vast carbon sink and a lifeline for nearby communities, providing clean water and fertile valleys through its network of rivers and watersheds.

Environmentalists describe it as a 'living shield'—a landscape that moderates rainfall, reduces the risk of floods and landslides, and stabilises the region's climate. Yet this critical ecosystem is under growing pressure from deforestation, mining, and large-scale infrastructure projects, which experts warn could diminish both its ecological and protective roles.

A Storm Chaser's Perspective

The belief that the Sierra Madre functions as a protective wall has drawn scrutiny from veteran storm chaser, Josh Morgerman, who travelled to the Philippines to document the fierceness of Typhoon Uwan.

Posting on Facebook, he wrote, 'Many folks are posting misinformation about the Sierra Madre Mountains in the Philippines. Let me set the record straight: The Sierra Madre chain weakens typhoons after they make landfall on the east coast of Luzon. These mountains do not protect the east coast of Luzon, which regularly experiences some of the strongest tropical‑cyclone impacts in the world.'

Morgerman's warning highlights a crucial point: while the range may influence storms after landfall, it does not prevent the most destructive winds and rainfall from reaching eastern Luzon.

The Myth and the Truth: Is It Really a Typhoon Barrier?

For generations, many Filipinos have believed that the Sierra Madre protects the country from the worst of typhoons. Positioned along Luzon's eastern flank, the range lies directly in the path of storms entering from the Pacific, hence the popular 'first line of defence' title.

When Super Typhoon Karding (international name: Noru) slightly weakened after crossing the range in 2022, this belief was reinforced. Then‑Interior Secretary Benhur Abalos even described it as 'our strongest defence against typhoons'.

Yet meteorologists and climate scientists agree with Morgerman's more cautious view. Dr Gerry Bagtasa, an atmospheric physicist at the University of the Philippines, explained that 'the range is not tall or high enough to have a significant impact in reducing the wind intensity of tropical cyclones'.

A 2023 study by Bagtasa and Racoma, published in the Philippine Journal of Science, found that while the Sierra Madre can lessen wind exposure and rainfall in parts of the Cagayan Valley, it does not significantly weaken tropical cyclones crossing Luzon. The researchers wrote that 'Luzon‑passing tropical cyclones maintain their intensities at landfall regardless of the frictional effects of the mountain ranges'.

Instead of functioning as an impenetrable barrier, the range tends to redirect and moderate storm energy. Its slopes can deflect winds and slow them briefly, but they also force moist, ocean‑fed air upward—a process known as orographic lifting—which can increase rainfall on the western side of the island.

Experts warn that believing in the mountain range as a natural 'storm shield' may lead to complacency in disaster preparedness.

Recent storms such as Typhoon Uwan underscore the point. As the 21st named typhoon of the year, Uwan struck the Philippines' eastern coast and triggered large-scale evacuation ahead of landfall.

The fact that eastern Luzon remains among the world's most exposed regions suggests that the mountains cannot guarantee protection. Moreover, ongoing deforestation, mining, and infrastructure development are steadily eroding whatever mitigating effects the Sierra Madre once provided. As the Inquirer puts it, 'The Sierra Madre continues to stand up to storms – but it needs protection from the very people it saves.'

A Shield, Not a Solution

In reality, the Sierra Madre serves as a moderator, not a miracle shield. It may temper some impacts of a typhoon after landfall, but it cannot prevent the initial strike.

True protection still relies on effective disaster planning, resilient infrastructure, and preserving the mountain range itself—measures that Filipinos continue to demand from their government.

As some have remarked, 'How many typhoons will the Sierra Madre need to "weaken" and "endure" before the government stops relying solely on resilience?'