THE SIERRA MADRE MOUNTAIN RANGE: EVALUATING ITS EFFECTIVENESS AS A NATURAL BARRIER AGAINST TROPICAL CYCLONES IN THE PHILIPPINES

This quantitative research evaluates the effectiveness of the Sierra Madre Mountain Range (SMMR) in Luzon, Philippines, as a natural barrier against tropical cyclones (TCs) that made landfall between 2015 and 2025. Utilizing a rigorous, retrospective quantitative content analysis of official best-track data from the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) and the Joint Typhoon Warning Center (JTWC), and disaster impact reports from the National Disaster Risk Reduction and Management Council (NDRRMC), the study assesses meteorological modulation (I and S) and correlates these changes with normalized socioeconomic damage metrics. The analysis focused on 18 TCs that traversed the SMMR over the study period. Findings reveal that the SMMR induced a marginal mean reduction in Maximum Sustained Wind speed (MSW) of 4.34%, which was determined to be not statistically significant (p=0.134 in a paired t-test), leading to the acceptance of the null hypothesis regarding wind mitigation. Conversely, the SMMR generated a statistically significant deceleration in translational speed (S), averaging a 23.25% reduction (p < 0.001). A strong positive correlation (r = 0.68) was established between S and Normalized Damage Cost (NDC) in densely populated leeward regions. The research concludes that the SMMR functions predominantly as a critical hydrological modifier rather than a robust wind shield, often amplifying cumulative precipitation risk and prolonging community exposure time.