Non‐monsoonal landslides in Uttaranchal Himalaya (India): Implications upon disaster mitigation strategy

Abstract

Purpose

Climatic conditions as also the agrarian economy of the Indian subcontinent is greatly affected by the monsoonal winds that are characterized by heavy rains between June and September. The paper is an attempt to break the myth that landslides are only confined to monsoonal months that normally have concentrated rains and can be expected in other seasons as well and, therefore, disaster alert levels cannot be relaxed during non‐monsoonal season. The communication also attempts to identify slowly ongoing weathering processes that might cause to slope failure without rains and, therefore, paves way for identifying similar landslide prone areas.

Design/methodology/approach

The paper discusses two landslides of the recent past; Uttarkashi landslide of 23 September 2003 and Ramolsari landslide of 30 March 2005 that took place after the seizure of the monsoonal rains and is based upon the first hand field observations of the authors. The paper discusses the likely causes of the slides along with the implications of this new trend of landslides taking place in the non‐monsoonal season upon the disaster management strategy of the state.

Findings

The investigations reveal that precipitation could be considered the trigger in case of Uttarkashi landslide but there exist no evidences to suggest that the Ramolsari landslide could have been triggered by increased pore water pressure. Slow ongoing and hard to observe processes of weathering seem to have initiated this slide.

Research limitations/implications

For the purpose of metrological parameters, the study relies upon the data of the state run rain gauges that do not have an appreciably good spatial distribution. Rainfall data of the nearest observation points is, therefore, taken as representative of the rainfall in the area under present focus. For Ramolsari, the rainfall data of Tehri is used while Uttarkashi has a rainfall recording observatory.

Originality/value

The paper highlights the importance of keeping the preparedness levels high for prompt post‐disaster operations all through the year. This paper advocates redefining high alert period for landslide hazard and for following high alert all through the year particularly in areas prone to landslides.

Citation

Rautela, P. and Pande, R.K. (2006), "Non‐monsoonal landslides in Uttaranchal Himalaya (India): Implications upon disaster mitigation strategy", Disaster Prevention and Management, Vol. 15 No. 3, pp. 448-460. https://doi.org/10.1108/09653560610669927