In the news this week...

Okay so maybe its not quite this week but its still worth a read. An article in The Guardian published on the 11th October 2011 highlights one of the potential impacts that glacial retreat may have on communities in the lowland valleys of the Himalayas. The article focuses on the pro-glacial Imja lake near Mount Everest which formed in the 1960s. Unlike normal floods, outbursts from pro-glacial lakes can occur repeatedly as glacial meltwater breaches the moraine dam on the leeward (downward) side of the valley. Goldenberg (2011) states that the lake is growing by around 47m a year, nearly three times faster than any other glacial lake in Nepal. This claim is partially supported by Bolch et al., (2011) study which estimated that the lake area had grown since 1960 to ~0.9km squared in 2003.

Due to its situation (5100m a.s.l), mobilising engineering equipment and expertise to attempt to mitigate against a glacial outburst is not an easy task. There is also the issue of predicting when the pro-glacial lake might flood compared to other lakes to assess how soon action needs to be taken to reduce the flood risk. Whilst the Nepali government ranks Imja as among the six most dangerous glacial lakes in the country, John Reynolds, a British engineer and supposed expert on glaciers argues that the gradual relief of the glaciers feeding the lake mean that it is a lower risk than other lakes in the region as ice is less likely to break off and cause a tsunami.

Nevertheless, there is the prospect that lake Imja, like many of the other 20,000 lakes in the Himalayas may flood at some point in the future. A prospect only increased as the glaciers continue to retreat. As the article concludes 'the question is how to decide which are hazardous now and which are going to become hazardous in the future'. (The Guardian, 2011).

Click here for a link to the video that accompanies this report.



Figure 1: Growth in Imja pro-glacial lake between 1992 and 2007 (Source: University of Maryland, 2008).

Reference:
Bolch, T., T. Pieczonka and D. I. Benn (2011) 'Mulit-decadal mass loss of glaciers in the Everest area (Nepal Himalaya) derived from stereo imagery', The Cryosphere, 5: 349-358.


The Guardian, ' Glacier lakes: growing danger zones in the Himalayas', Tuesday 11th October 2011.