A scientific analysis of the reasons for the disaster that struck Uttarakhand, particularly the temple town.
THE primary trigger for the Uttarakhand disaster following the very heavy rain during June 16-18 was the extremely unusual behaviour of the monsoon this year over north India. The incessant, heavy rainfall over three days, perhaps accompanied by a few cloudburst-type events (which cannot be confirmed), resulted in flash floods and associated landslides. The devastation all round in their wake has been huge but the largest impact has been at the temple town of Kedarnath, which was in the midst of the annual pilgrimage season, with tens of thousands of people thronging the town and the downstream region along the Mandakini river .
1). Rainfall measurements for June 16 and 17 at the Dehradun station, of 220 millimetres and 370 mm respectively, indicate the severity of the rain during these days in the region. Haridwar received 107 mm and 218 mm of rainfall on the two days. Uttarkashi received 122 mm and 207 mm. While Mukteshwar (altitude over 2,000 metres) received 237 mm and 183 mm respectively on June 17 and 18, Nainital on the same days received 176 mm and 170 mm. Though rainfall over a 24-hour period in different parts of Uttarakhand has greatly exceeded these figures in the past (on many occasions above 450-500 mm and once even 900 mm at Rajpur near Dehradun), prolonged heavy rainfall for nearly three days over a large area is perhaps unprecedented, and the cumulative effect, compounded by geophysical, meteorological and environmental factors, may be the reason for the enormity of the disaster. More pertinently, these numbers do not give the actual quantitative picture of the very heavy rainfall in the higher reaches of the Himalayas (above 3,000 m) in Uttarakhand, where Kedarnath, Gangotri and Badrinath are located and where the impact has been most severe. This is because the rain gauge stations of the India Meteorological