AUTHOR=Azizah Cut , Robo Sarif , Misnawati Misnawati , Lizar Cut Ayu , Zubaidah Sitti , Taufik Muh 
  
TITLE=Potential flash flood dynamics in the humid tropics: insights from three basins in Sumatra
  
JOURNAL=Frontiers in Water
  
VOLUME=Volume 8 - 2026
  
YEAR=2026
  
URL=https://www.frontiersin.org/journals/water/articles/10.3389/frwa.2026.1800323
  
DOI=10.3389/frwa.2026.1800323
  
ISSN=2624-9375
  
ABSTRACT=Flash floods in humid tropical mountain basins are highly destructive hydrometeorological hazards, yet comparative studies that integrate geomorphological and hydrometeorological conditions remain limited. This study aims to identify and synthesize potential flash flood dynamics in three mountain basins in Sumatra, namely the Peusangan, Wampu, and Anai basins, through an integrated analysis of six key parameters: basin morphometry, high landslide susceptibility zones on steep slopes, land use related modeled runoff potential, event rainfall, antecedent wetness, and antecedent soil moisture. The results indicate that the three basins exhibit contrasting physical characteristics and hydrological response potential. The Wampu Basin has the highest drainage density, at 5.41 km/km2, but also the longest time of concentration, at 28.8 h, whereas the Anai Basin has the shortest time of concentration, at 5.8 h. Spatial linkage between susceptible slope areas and the river network is stronger in the Peusangan and Anai basins, whereas in the Wampu Basin, 47.0% of susceptible slope areas are located more than 500 m from the drainage network. Land use related modeled runoff potential is most evident in the Peusangan Basin, where the runoff coefficient increases from 0.34 to 0.36 and runoff volume increases from 82.67 to 87.91 million m3, while changes are more limited in the Wampu and Anai basins. From a hydrometeorological perspective, event rainfall estimates range from 8.1 to 13.4 mm/h, while 5 day antecedent rainfall reaches 114.4 to 186.5 mm. Satellite and reanalysis based antecedent soil moisture indicators suggest wet to high moisture conditions before the events, with near saturated and saturated classes present within the basins. Overall, potential flash flood dynamics in these humid tropical mountain basins can be interpreted through the combined information from preconditioning factors and triggering rainfall. The comparative framework developed in this study provides a basis for preliminary flash flood assessment and disaster risk reduction in data scarce humid tropical regions.