China Meteorological Administration, in collaboration with the Ministry of Water Resources and the Ministry of Natural Resources, establishes an impact-based early warning system for flash floods and geological disasters

In coping with complex extreme weather events and their resultant cascading secondary disasters, the China Meteorological Administration (CMA), guided by the concept of Impact-based Forecast and Warning Services (IBFWS) advocated by the World Meteorological Organization (WMO), has deeply implemented Paradigm 3 regarding inter-agency collaboration as outlined in the WMO Guidelines on Multi-hazard Impact-based Forecast and Warning Services (WMO-No. 1150). Consequently, CMA has established a multi-hazard impact-based forecasting and warning operational system, pioneered by meteorological early warnings and characterized by in-depth multi-sectoral collaboration. Within this national disaster risk reduction (DRR) framework, CMA, through the precise identification of meteorological hazard factors and the provision of high spatio-temporal resolution precipitation monitoring and forecasting, has constructed a dual-track parallel meteorological risk forecasting and warning operational system in conjunction with the Ministry of Water Resources (MWR), which is responsible for flash flood disaster warnings, and the Ministry of Natural Resources (MNR), which is responsible for geological hazard (e.g., landslides and debris flows) warnings, respectively.

Within the joint early warning mechanism for flash flood disasters, CMA and MWR have established an in-depth collaboration mechanism regarding models and data. Both parties jointly researched and formulated the grading standards for flash flood meteorological risk warnings, establishing a four-tier warning system consisting of Blue, Yellow, Orange, and Red alerts. In this context, CMA spearheads the precise identification of meteorological hazard factors, assumes responsibility for high-resolution precipitation monitoring and forecasting as well as the simulation of hydrological models for flash floods, and couples multi-source hazard factors with MWR's early warning model, which is based on the exposure and vulnerability information of elements at risk (encompassing hidden disaster hotspots, prevention and mitigation zoning, and census data). Through joint consultations between the meteorological and water resources sectors, the risk areas (footprints) under various impact levels are determined (i.e., delineating risk areas of different severities based on respective impact-based warning thresholds). Consequently, national flash flood early warning guidance products are generated on a daily basis.

Regarding the joint early warning mechanism for geological hazards, CMA, in collaboration with MNR, has established a three-tier (Yellow, Orange, and Red) meteorological risk warning standard for geological hazards, along with its production and dissemination protocols. Here, the meteorological sector utilizes the characteristics of long-duration accumulated precipitation and short-term (nowcasting) extreme precipitation as the hazard-driving forces. This is deeply integrated with information provided by the natural resources sector, including geological hazard susceptibility zoning, census coordinates of hidden risk hotspots, and geotechnical exposure data. Drawing upon the forecasting results from geological hazard risk models developed by both parties, joint consultations are conducted to delineate the risk areas under different impact levels. Accordingly, national geological hazard early warning guidance products are issued twice daily.

Building upon national-level early warning products, China has comprehensively implemented a top-down cascaded dissemination mechanism. The national-level meteorological authority guides the meteorological departments at the provincial, municipal, and county levels to sequentially issue more refined flash flood and geological hazard warnings jointly with their counterparts in the water resources and natural resources sectors at the respective levels. This vertically integrated and horizontally coordinated architectural paradigm has significantly enhanced the authoritativeness and coverage of early warning information. Thus, it substantially supports local governments at all levels in executing disaster emergency responses and the evacuation and relocation of at-risk populations, thereby tangibly realizing the highly efficient transformation from the "issuance of forecasts" by official authorities to the implementation of "Actionable Responses" by society.