This paper documents the emergency response to breaches of the Baige barrier lake. The lake was formed by landslides that occurred on October 10 and November 3, 2018 at the border between China’s Sichuan and Tibet regions. The barrier lake created by the “10.10” landslide breached on October 12 and released a flood with a peak discharge of 10,000 m3/s. The residual landslide dam was covered by the second landslide on November 3, resulting in an even bigger lake that had the potential to release an even larger flood. A diversion channel was excavated to make the breach take place at a lower water level. The second breach happened on November 12 and had a measured peak discharge of 31,000 m3/s. Nearly 75,000 people were evacuated before the two breaches. In order to avoid the possible overtopping of a downstream dam, nearly 5.78′108 m3 of stored water was released from the reservoir behind that dam. This paper presents the measured hydrographs and the back-analysis results for the “11.03” Lake breach. It is shown that modern dam breach hydraulics can reasonably reproduce the breach hydrographs. However, more work is needed to gain insight into which parameters influence the calculated results the most. Experience gained from this case can be shared with experts working on breaches of earthen dams and promote our ability to combat this type of natural disaster.

Data availability statement：
The following data are available for download at the following website:
http://www.geoeng.iwhr.com/geoeng/download.htm.
1. Computer programs in Excel and data of the cases contained in Table 5.
2. Flood propagation simulation for the 11.03 breach.
(1) The computed and measured hydrographs shown in Fig. 30.
(2) Input of the terrain data.
(3) Input of flow at the breach.
For the related computer programs and user manual, please contact the
corresponding author of this paper.