An enormous wall of water and particles swept down the Teesta valley within the japanese Himalayas on October 3 2023, inflicting well-liked devastation and the tragic lack of over 50 folks. This robust flood in India was once the results of a landslide which led to a glacial lake upper up the valley to spill over. This phenomenon is referred to as a glacial lake outburst flood, or GLOF.
In a 2025 find out about of glacial lakes around the Bolivian Andes, my colleagues and I discovered that 11 are extremely liable to generating doubtlessly hazardous GLOFs. Such lakes are expanding in measurement and quantity as glaciers retreat world wide. In Bolivia, we noticed 60 new lakes shape in simply six years.
Over the similar six-year duration, glaciers within the area shrank abruptly. In the event that they proceed to soften on the similar charge, Bolivia will likely be solely ice loose through the 2080s. Sadly, that is more likely to be a conservative estimate.
We modelled the form of the land floor beneath the present ice to expect the place lakes would possibly shape in long run. We discovered greater than 50 possible lake websites. Additional tracking will confirm which of those rising lakes would possibly pose a chance to downstream populations or infrastructure.
In our find out about, we used excessive solution satellite tv for pc imagery to watch glaciers and glacial lakes around the Bolivian Andes. We mapped glacier and lake barriers at annual durations between 2016 and 2022.
Bolivia is house to just about one-fifth of the sector’s tropical glaciers. Those glaciers are vital in their very own proper, specifically all the way through the dry season, when meltwater supplies very important provides for human intake, agriculture and business. Glaciers additionally play a task within the cultural existence and heritage of Indigenous peoples on this area.
We discovered an alarming charge of shrinkage amongst those glaciers. Between 2016 and 2022, the overall floor space of glaciers in Bolivia reduced through just about 10% – at a median charge of virtually two sq. miles in keeping with yr. If those glaciers proceed to retreat on the similar charge, there will likely be none left within the area through the 2080s.
Floor space (blue bars) and selection of lakes (crimson line) through yr.
Jamie MacManaway, CC BY-NC-ND
But this represents a perfect case state of affairs. As glaciers get smaller, they shrink extra abruptly, so the velocity of decline will almost definitely building up through the years.
Such fast deglaciation now not handiest threatens water safety however might also injury ecosystems. Within the Andes, high-altitude wetlands referred to as “bofedales” retailer huge quantities of carbon and assist soak up water too. Must they dry out because of lowering water availability, they are going to unlock the carbon they’ve been storing – using additional warming of the ambience.
As glaciers melted and shrank around the area, the quantity and measurement of glacial lakes higher. Round 60 new lakes shaped over the process the find out about duration. Many of those lakes had been small and can be not going to supply a GLOF able to doing vital injury, however 120 had been regarded as sufficiently big to constitute a possible danger.
We analysed those lakes with a view to assess their susceptibility to generating a GLOF and located that 11 had been worthy of additional investigation. For instance, ascertaining the possible penalties on downstream populations of an outburst flood from this sort of lakes may assist to tell long run tracking and mitigation efforts.
To scale back the danger of long run disaster, native communities can get ready in a spread of the way. That comes with the bodily building of spillways and diversion canals, strategic land-use making plans and the design of flood-resistant infrastructure. Crisis preparedness additionally calls for social measures, comparable to schooling and consciousness elevating in order that citizens perceive obviously communicated evacuation plans or early caution techniques.
Modelled lakes within the Cordillera Actual, Bolivia. Blue lakes are the ones predicted to shape given endured glacier recession, whilst cyan lakes had been as it should be predicted through the fashion to shape between 2000 and 2022. Pink lakes are the ones predicted through the fashion which failed to shape.
Jamie MacManaway, CC BY-NC-ND
Modelling the hollows
The use of current world glacier thickness information blended with our findings, we created a virtual fashion representing the form of the land floor beneath the ice. Glaciers are immensely robust erosive brokers and will carve deep hollows into the bedrock that they trip over. Because the ice retreats, those hollows ceaselessly fill with water and grow to be lakes.
We discovered 55 possible long run lake websites. Now not all of those lakes will indubitably shape. Shallow depressions would possibly fill with sediment as a substitute of water whilst deeper ones could also be tired through gorges which is able to’t be detected through modelling as a result of they’re simply too slender for the tech to search out. Fashions can be much more dependable with get admission to to raised solution datasets which don’t seem to be these days to be had for the Bolivian Andes.
Long run lakes throughout Bolivia would possibly constitute vital resources of water – partly offsetting the results of dropping glacial meltwater. However, those lakes could also be liable to generating GLOFs, so fast and sustained global motion to scale back the impact of local weather alternate at the international’s glaciated areas is significant.
