Short-rise-time gusts in mountainous terrains are highly transient flows characterized by rapid variations in wind speed and wind direction over very short durations. These extreme wind gusts play a critical role in affecting the safety and operational performance of various wind-sensitive infrastructures within the engineering community. However, field measurement studies of their wind characteristics remain limited, primarily due to their rarity and localized nature. Therefore, based on the long-term wind field data spanning 834 days collected by ultrasonic anemometer in a plateau mountain valley, the motivation behind this study is to focus on short-rise-time gusts with time scales of less than 10-min, aiming to ensure that rapid variations in wind speed and direction are accurately captured without being artificially smoothed or masked by the fixed 10-min averaging interval. First of all, a five-step approach is developed to identify multi-scale extreme wind gusts, covering time scales from seconds to minutes. Subsequently, the time scale parameters and wind characteristics of the identified sudden-rise-time gusts are comprehensively investigated because of their potential adverse aerodynamic and aeroelastic effects on flexible structures. Finally, the commonalities and differences between the short-rise-time gusts and the non-sudden winds are compared. The outcome of this study is expected to enhance the understanding of the complex behaviors inherent to these extreme gusts and provide valuable insights for wind-related risk assessments of various wind-sensitive infrastructures in mountainous terrains.

Bridge engineering;Wind engineering;Short-rise-time gusts;Wind characteristics;Mountainous terrain;Field measurement