Planning n Mitigation | VOL. 13, ISSUE 79, July-August 2013 |
The extreme rainfall, floods and landslides that occurred in Uttarakhand during 16-18 June 2013 has caused unprecedented deaths and destruction of property. People have asked if we could have avoided the tragedy through an advanced warning system and enforcement of building laws. The phenomenon of extreme rainfall and floods occur all over the world but we do not see as many deaths as most countries have a good advance warning system. The consequence of extreme rainfall can be predicted accurately. A high resolution terrain data can be used to convert rainfall rate to flood levels at various points along the course of the river. For the purposes of flood prediction, the rainfall rate can be calculated based on cloud data from a geostationary satellite. In addition, rainfall prediction by weather forecast models, two to three days in advance, is adequate for flood prediction. Hence a warning about potential flood and landslides in Uttarakhand could have been given on the evening of 16th June 2013 based on the forecast available on the website of India Meteorological Department (IMD) on 15th June 2013. Such a warning could have saved thousands of lives in the Mandakini valley in Kedarnath. This was not done because of the mistaken belief that the rainfall predictions are not accurate and the remarkable improvements that have occurred in short-term rainfall forecasting during the past decade was not appreciated by the National Disaster Management Authority (NDMA). There are hundreds of automatic rain gauges in India which can be designed to send an alarm through the mobile network to any district official as soon as the rainfall rate exceeds a certain threshold. These actions do not cost much and can be implemented fairly quickly. In country that has hundreds of TV channels it is surprising that we do not have a channel devoted solely to weather, climate and extreme events. Such a channel would have increased awareness among our people about the consequences of extreme rainfall in the Himalayas.
The destruction of a large number of buildings in Uttarakhand was on account of the gross violation of building laws. The number of new buildings that have been permitted near the banks of the river during the past 20 years in Uttarakhand is astounding. In Kedarnath, there were few buildings around the temple 30 years ago. The construction of a large number of ugly concrete structures around the temple not only destroyed the beautiful ambience of this valley but it also contributed directly to a large number of deaths that occurred as a consequence of debris slide. Ten years ago the Geological Survey of India (GSI) had pointed out that the area around the temple was vulnerable to landslides and suggested that the pilgrims should stay near the region where the present helipad is located. If this suggestion had been implemented, most pilgrims would not have succumbed to the debris slide that occurred on the morning of 17th June 2013. The threat of landslide is indeed large in Uttarakhand after heavy rainfall as most of the hills in the outer Himalaya are made of river debris. Most landslides occur during July and August when the rainfall in normally high. This year the heavy rainfall unexpectedly occurred in June. There are simple methods available to predict the probability of landslide based on accumulated rainfall thresholds and these should have be used by NDMA to provide a map of ‘landslide threat’ on their website. They should have provided training to the travel agencies that bring pilgrims to Uttarakhand so that they unmistakably comprehended the threat. When you enter a mountainous region in developed countries there are clear warning signage on the road about possible avalanches and landslides along stretches. If such a practice existed in India, many tourists and pilgrims would have decided not to go beyond Rishikesh.
But could we have predicted the catastrophic debris slide that occurred on 17th June morning in Kedarnath on account of bursting of a lake? Perhaps one could
have predicted that the probability of a flood was high but the precise prediction of debris slide would have been more difficult. This would have demanded the monitoring of high latitude lakes and associated landslides in the region. Since millions of pilgrims visit Uttarakhand each year it may be necessary in future to monitor few of the lakes that pose a direct threat to the four valleys visited. There is an urgent need to establish an institution that can provide maps of regions prone to landslide threat after a heavy rainfall episode. Such institutions exist in many Asian countries. And as fragile as Uttarakhand is, with a double threat from both earthquakes and extreme rainfall—it is absolutely imperative that an advance warning system may be established here as soon as possible.