About 140 mm triggered 143 landslides in an area of about 10 km2, killing two people.
Loyal readers will have noticed that I’m fascinated by dense clusters of landslides triggered by intense rainfall (or earthquakes). Over the years, I have written about these on multiple occasions, but increasing numbers are being described in the literature.
Another very interesting example has just been published in the journal Landslides (Xie et al. 2025). This example occurred on 12 July 2024 close to Puzi in Pengshui County, Chongqing, China. The centre of the cluster as at [29.56790, 108.28781] – this is the marker on the images that follow.
The Planet image below shows the area on 24 May 2024, before the rainfall:-
And this is the same site after the event on 12 July 2024:-
And here is an image compare:-
Xie et al. (2025) show that this cluster of landslides was triggered by a rainstorm that deposited about 140 mm of rainfall in a few hours. In total, 143 landslides were triggered in an area of about 10 km2. The failures were mostly disrupted avalanches, some of which formed channelised debris flows. However, Xie et al. (2025) also show that there are a number of interesting aspects of this cluster of landslides.
Note the geographical isolation of these landslides. The slopes to the east and west suffered far fewer failures. Perhaps surprisingly, this cluster of landslides did not occur in the area of highest rainfall – a short distance to the west, more than 200 mm was recorded, but few landslides occurred.
The analysis of Xie et al. (2025) shows that this cluster occurred because of a weak geological unit (sandstone) that was highly fractured, a geological structure that promoted instability and steep slope gradients (which may be associated with erosion by the river). Thus, it is the combination of the meteorological, geological and geomorphological factors that led to the cluster of landslides.
Fortunately, the area had been mostly evacuated ahead of the rainfall, so there were just two fatalities. There was extensive damage to properties though.
This event illustrates well the ways in which extreme rainfall events are combining with local factors to create clusters of landslides that have the potential to generate high levels of damage.
Many thanks to Xie et al. (2025) for such an interesting example.
References
Xie, X., Liu, S., Macciotta, R. et al. 2025. Spatial heterogeneity in landslide response to a short-duration intense rainfall event on 12 July 2024 in Pengshui County, Chongqing, China. Landslides. https://doi.org/10.1007/s10346-025-02624-6.
Planet Team 2025. Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. https://www.planet.com/.