The Landslide Blog is written by Dave Petley, who is widely recognized as a world leader in the study and management of landslides.
I have now compiled the provisional list of fatal landslides in September 2024, which allows me to provide an update on the year to the end of the month.
The headline is that a year that has always been exceptional has now become even more so. However, there is an unusual amount of uncertainty in the data that I am presenting for two reasons, which I’ll outline below.
The simple facts at the moment are these. In September 2024, I recorded 155 fatal landslides – by far the largest monthly total in my records. These claimed 616 lives, which is also an unusually large total.
The principal driver for this large total was the exceptional monsoon rainfall event struck Nepal late in the month. I downloaded data from the official disaster database (Bipad) last week – at that stage it had records of 92 fatal landslides killing 203 people in this single rainstorm. This is event has had a huge impact on the global monthly total.
I suspect that there is some uncertainty in these numbers for Nepal, and they will need to be revisited in due course. It is possible that there are some duplicate records, but time will tell. However, even if this proves to be the case, the total will still be remarkable.
At this stage, I am taking this data at face value as this is the official dataset. This is the resulting graph in terms of fatal landslides per month to the end of September 2024:-
Loyal readers will also know that I like to present this data as pentads – five day blocks. In this series of posts I have used 2018 and 2019 for comparison as “typical” years. This how the cumulative total now looks to the end of September:-
The total number of landslides in 2024 to the end of September now far exceeds any previous year, and there are still three months of the year to go.
If we exclude the Nepal rainfall event, 2024 still looks exceptional. I recorded 63 other fatal landslides in September. This total alone exceeds any previous September for which I have records (the previous highest total was 48 in both 2009 and 2010).
There is one final caveat. Hurricane Helene deposited a vast amount of rainfall across parts of the United States, triggering at least 230 landslides according to the USGS (with mapping work still underway). The USGS has a web page detailing its ongoing work to understand the landslides triggered by this storm. I have recorded just three fatal landslides from this event, one in each of Swannanoa, Garren Creek, and Avery County in North Carolina. This is likely to be an underestimate, but information on specific events that led to loss of life is hard to find.
If anyone knows of any other fatal landslides from Hurricane Helene, I would be grateful for your help. Or, if anyone knows where this data is collated for this event, please could you let me know.
I will emphasise once again that the data for September 2024 has more uncertainty than is normally the case, but there is no doubt that it continues the exceptional landslide pattern that we have seen through 2024.
