The authors look at the challenge of predicting post-monsoon and winter precipitation, and how the global climate crisis is affecting rainfall patterns that used to be fairly regular in the past. The paper analyses precipitation data since 1971 to show that total post-monsoon rains have gone down all over Nepal except parts of the trans-Himalaya.
‘Existing meteorological stations are inadequate to cover the diversity of Nepal’s microclimates, and the high mountain and remote regions have fewer stations than required for climate trend analysis,’ the paper notes.
The authors also look into why there was widespread damage and human casualties despite weather alerts through media. Although the Department of Hydrology and Meteorology did predict rain, the messaging did not include location and time-specific impact-based forecasting, they say.
Although the National Disaster Risk Management and Mitigation Authority (NDRMMA) did issue early warnings through social media platforms, including daily situation reports, the paper says that these tended to focus on post-event rescue and relief, and not enough on early warning.
Even when the correct forecast was available, there was not enough coordination with various other agencies of government like the Ministry of Agriculture, the Ministry of Local Development, local governments, as well as the security agencies for emergency rescue.
This could have been due to the impending Dasain holiday mood, but the authors also blame ‘location specific impact-based rainfall forecasts’. In other words, the early warning was too general. The authors imply that the Department of Hydrology and Meteorology should not just be in the business of issuing forecasts, but also work with local authorities for preparedness and timely action.
‘The argument that the frequency of extreme rainfall events in the post-monsoon has increased seems to be valid,’ the paper says. ‘In 2009, the post-monsoon high rainfall was concentrated in west Nepal. It was the same initially in 2021, but the widespread and unseasonal rainfall last year seemed to catch everyone by surprise and there was not even some semblance of preparedness for rescue and relief to be dominant in disaster management response.’
24-hour rainfall 18-19 October. Source: DHM
24-hour rainfall October 19-20. Source: DHM
24-hour rainfall October 20-21. Source: DHM
Stations with over 200 mm of accumulated rainfall in 2021 October
Maximum 24-hour October rainfall above 140 mm in October (1951 to 2009)