Wu et al. (2026) Analysis on Multi-Factor Synergistic Hazards Mechanism of Wet Micro-Downburst: a Multi-Source Data Fusion Analysis Based on Passenger Vessel Capsizing Accident in Qianxi, Guizhou on 4 May 2025

Identification

• Journal: Natural hazards and earth system sciences
• Year: 2026
• Date: 2026-03-31
• Authors: Ankun Wu, Xi Guo, Dan Yao, Xiaoling Du, Dongpo He, Jue Long Li, Shisheng Jin, Tienan Bai
• DOI: 10.5194/nhess-26-1561-2026

Research Groups

• GuiZhou Meteorological Administration Data Center, Guiyang 550002, China
• Guizhou Meteorological Disaster Prevention Center, Guiyang 550002, China
• Meteorological Observation Center of CMA, Beijing 100081, China
• Meteorological Observatory of Guizhou, Guiyang 550002, China

Short Summary

This study investigates the multi-factor synergistic mechanism of a wet microburst that caused a passenger vessel capsizing accident in Qianxi, Guizhou, on 4 May 2025, by fusing multi-source data to reconstruct the event and elucidate the dynamic-microphysical coupling. It found that a rapidly descending strong radar echo core triggered an explosive near-surface divergent wind field (34.7 m/s), accompanied by significant temperature and pressure changes, and verified by lightning activity, surveillance videos, and on-site damage.

Objective

• To systematically analyze the multi-factor synergistic disaster-causing mechanism of wet microbursts, focusing on the "5.4" passenger ship capsizing accident in Qianxi, Guizhou, on 4 May 2025.
• To reconstruct the complete formation and evolution process of the wet microburst using multi-source data.
• To elucidate the disaster-causing mechanism of dynamic-microphysical coupling.
• To fill the gap in multi-source data fusion analysis of wet microbursts in inland waters and provide scientific support for early warning and emergency response.

Study Configuration

• Spatial Scale: Dongfeng Reservoir, Qianxi, Guizhou Province, China (microburst scale, 4 m to 4 km). Specific locations include Huawu Village Meteorological Observatory, automatic weather stations R7676 and R7657, Shoubayan, and a wharf square.
• Temporal Scale: Event occurred on 4 May 2025, 08:32 UTC. Surface meteorological data covered 3 hours before and after the event at minute-level resolution. Weather radar data spanned 08:18 to 08:48 UTC. Lightning monitoring data covered 08:00 to 09:00 UTC.

Methodology and Data

• Models used: No explicit numerical models were used; the study is based on multi-source observational data fusion and analysis.
• Data sources:
  • Weather radar observations: Multi-band composite reflectivity factor, Guiyang S-band weather radar data (reflectivity factor (REF), radial velocity (VEL), differential reflectivity (ZDR)).
  • Surface meteorological observations: Minute-level instantaneous data (temperature, humidity, pressure, precipitation, wind speed/direction) from automatic meteorological stations (R7676, R7657).
  • Lightning monitoring data: Guizhou Province 3D Lightning Monitoring Network (total flashes, cloud flashes, cloud-to-ground flashes).
  • On-site surveillance videos: Real-time videos from cameras at Shoubayan and the wharf.
  • Disaster trace investigations: Field damage traversal, spatial correlation analysis, and measurements of uprooted tree trunks.

Main Results

• A strong radar echo core (intensity > 50 dBZ, up to 74 dBZ) rapidly descended from 6-8 km to 2-4 km, reaching its lowest altitude (near 2 km) between 08:29 and 08:34 UTC, coinciding with the occurrence of maximum ground wind speed.
• An explosive near-surface divergent wind field was observed, with an instantaneous wind speed of 34.7 m/s (exceeding wind force level 14) recorded at Station R7676 around 08:32 UTC. The wind direction abruptly shifted from northeasterly (56°) to westerly (near 270°).
• Surface temperature plummeted by 14.9 °C within 10 minutes (from approximately 30 °C to 16.1 °C), and atmospheric pressure surged by 540 Pa within 5 minutes, indicating a significant cold pool outflow.
• A high ZDR region (2 dB) appeared at 2-4 km altitude, below the 0 °C layer (5 km), indicating the dominance of flattened water droplets formed by melting ice-phase particles, which enhanced near-surface cooling and downdraft momentum.
• The VEL profile showed a negative velocity region (downdraft) at 4-8 km extending downward, and a near-surface positive velocity zone expanding, forming a divergent field consistent with Fujita's classic downburst model.
• Lightning activity exhibited a high proportion of cloud flashes (85.1%) and a strip-like northwest-southeast distribution, spatially and temporally coinciding with convective cell paths and intense echo cores.
• Video surveillance and on-site disaster traces (directional tree lodging, bidirectional wall damage, wind direction reversal + hail) corroborated the radar and surface observations, verifying the synergistic disaster-causing chain of dynamic-thermal-microphysical coupling.
• Estimated instantaneous wind speeds from tree damage ranged from 28.3 to 36.1 m/s, consistent with ground station observations.

Contributions

• Fills a critical gap in multi-source data fusion analysis of wet microbursts, particularly for inland water disaster research.
• Provides a systematic analysis integrating minute-level high-resolution observations (weather radar, surface meteorological, lightning, on-site surveillance videos, and disaster traces) to overcome limitations of single-source or low-resolution data in previous studies.
• Elucidates the multi-factor synergistic disaster-causing mechanism of wet microbursts through a coupled analysis of dynamics, microphysics, and surface responses.
• Proposes multi-factor collaborative criteria for severe convection warning in complex terrain areas.
• Offers vital scientific support for optimizing early warning and emergency response strategies for similar water vessel capsizing disasters.

Funding

• Guizhou Provincial Basic Research Program (No. Qiankehe Jichu MS (2026)339)

Citation

@article{Wu2026Analysis,
  author = {Wu, Ankun and Guo, Xi and Yao, Dan and Du, Xiaoling and He, Dongpo and Li, Jue Long and Jin, Shisheng and Bai, Tienan},
  title = {Analysis on Multi-Factor Synergistic Hazards Mechanism of Wet Micro-Downburst: a Multi-Source Data Fusion Analysis Based on Passenger Vessel Capsizing Accident in Qianxi, Guizhou on 4 May 2025},
  journal = {Natural hazards and earth system sciences},
  year = {2026},
  doi = {10.5194/nhess-26-1561-2026},
  url = {https://doi.org/10.5194/nhess-26-1561-2026}
}