Fatal landslides in 2010: a half term report

Long term readers of this blog will know that one of its original purposes was to disseminate the work that I do collating data on fatal landslides worldwide.  As the Attabad situation reduces in its intensity I plan to return to some of those key themes.  So here is a half term report on the occurrence of fatal landslides in 2010.

Numbers of landslides:
As of the end of 30th June I had recorded a total of 235 fatal landslide events worldwide, with a distribution by month that looks like this:

This is the highest number of fatal slides for the first six months of the year that I have recorded to date (i.e. since 2003).  In comparison, this graph shows the cumulative total number of fatal landslides for 2010, for 2009 (the previous record) and on average across 2003-2009:

So clearly the number of landslides is running well ahead of the norm for the end of June (remember that globally the main landslide season is in July to September due to the effects of the Asian monsoon.  It is not clear why this should be the case, but it may be associated with the transition from El Nino to La Nina conditions. 

Loss of life:
The number of recorded fatalities is 2,168, with the monthly distribution looking like this:

Again, this is much higher than for an average year, as the cumulative total plot demonstrates.  Note that the previous highest year was 2006 in this case - 2010 is just below this total, but has shown a consistent trend throughout:

Largest events:
The largest event in terms of recorded numbers of fatalities was the 2nd March 2010 landslide at Nametsi Village, Bududa in Uganda, which killed 358 people.  However, the numbers killed by landslides in the Haiti earthquake remains unknown.


Worst affected countries:
The top ten countries in terms of numbers of fatalities is as follows:

1	China	467
2	Uganda	373
3	Brazil	334
4	Guatemala	184
5	Indonesia	118
6	Peru	103
7	India	90
8	Pakistan	61
9	Bangladesh	55
10	Kenya	23

Given the high level of landsliding so far this year, the next few months will be interesting.

Fatal landslides in S. Asia in 2009

The key driver of landslides in S. Asia is the SW (summer) monsoon, which brings prolonged and sometimes heavy rainfall across much of the Indian subcontinent. This year the monsoon has been comparatively weak so far, with only a month or so to go. Indeed, the Indian Institute of Tropical Meteorology maps of the total monsoon rainfall give a picture of considerable rainfall deficit, although it should be noted that heavy rainfall in the last few days may have started to reduce this:So I wondered to what degree this is being reflected in the landslide pattern for S. Asia. The graph below shows the monthly occurrence of rainfall-induced fatal landslides for S. Asia for the period 2002 to 2008, with the 2009 figures up to the end of August included (click on the graph to view a bigger version in a new window):

The black line is the long term average, and red line is 2009. I have used a lighter line for previous years to make the graph clearer. As I have pointed out previously for similar graphs, this graph shows clearly the impact of the monsoon, with a clear, asymmetric summer peak and low levels the rest of the year. Note that there is some inter-annual variation, with 2007 and 2008 varying somewhat from the patterns seen in other years for reasons that are not at all clear.

So what of 2009? Well, perhaps surprisingly 2009 shows a very unexceptional picture. May was somewhat above average, and June below, whilst July and August are almost exactly as per the long term mean. There is some evidence that in previous El Nino years September has been the month with the most intense rainfall in S. Asia, so it will be interesting to see what is to come.