DOST, US storm chaser debunk myths on Sierra Madre’s typhoon shield
MANILA, Philippines — The Department of Science and Technology (DOST) and American storm chaser Josh Morgerman have explained the long-held belief that the Sierra Madre mountain range fully shields Luzon from typhoons.
Morgerman, who is in the Philippines to document Super Typhoon Uwan (international name: Fung-wong), said that while the Sierra Madre weakens cyclones after they hit land, it does not protect the eastern coast of Luzon from direct impact.
"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 wrote on his Facebook page.
Uwan developed into a super typhoon on Sunday before weakening as it moved across Luzon.
Sierra Madre's limits
The DOST's post is similar to Morgerman’s comment, citing a 2023 study published in the Philippine Journal of Science by Drs. Gerry Bagtasa and Bernard Alan Racoma. The research used weather models to analyze 45 typhoons that struck Luzon between 2000 and 2020.
According to the study, the Sierra Madre can help reduce wind strength by 1% to 13% but cannot fully shield Luzon from a typhoon’s impact.
The range also enhances rainfall in the western part of Luzon by 23% to 55%, while mitigating both wind and rain effects in the Cagayan Valley.
“Mas malaki pa rin ang pinsalang dulot ng malalakas na pag-ulan at pagbaha kaysa sa mismong hanging dala ng bagyo,” the agency added.
The study found that typhoons typically retain their strength during the first six hours after landfall—even in areas with mountains—and concluded that the Cordillera range has a “larger hazard-mitigating effect” than Sierra Madre.
The post and study emphasized the urgent need to protect the Sierra Madre from illegal mining, deforestation and other hazardous activities that endanger its biodiversity. Sierra Madre is host to 3,500 plant species of which 58% are endemic.
“Maaaring sabihing nakatutulong ang Sierra Madre Mountain Range bilang panangga sa mga bagyo sa Luzon sapagkat may kakayahan itong bahagyang pahinain o bagalan ang lakas ng hanging dala ng bagyo — lalo na sa hilagang-silangang bahagi ng rehiyon. Gayunman, hindi ito nagbibigay ng ganap na proteksyon laban sa matitinding epekto ng mga ito,” DOST wrote on Facebook.
RELATED: ‘Protect Sierra Madre at all costs’: Luzon’s mountains trend amid Super Typhoon 'Uwan'
