Following the Glacial Lake Outburst Flood (GLOF) reported at Sintaphu Tsho (Shintaphu Lake) in Bhutan’s Gasa district on October 29, 2026, Suhora Technologies, a Noida-based geospatial intelligence company, conducted a near-real-time satellite-based assessment to analyse the impact of the event on the glacial lake system.
The incident resulted in the complete destruction of facilities at Gasa Tshachu, a popular natural hot spring situated along the banks of the Mo Chhu River in northwestern Bhutan, and also triggered flash flood warnings for parts of West Bengal and Assam.
For its post-event assessment, Suhora analysed high-resolution (1-metre) Synthetic Aperture Radar (SAR) satellite imagery acquired on October 30, 2026, at 16:50:32 UTC (22:20:32 IST). The assessment revealed changes in the surface area and estimated volume of Sintaphu Tsho and the adjoining supraglacial lake.
Key Findings from the Post-Event Satellite Assessment:
Sintaphu Tsho (Main Lake)
- Surface area decreased from 24.13 ha to 6.54 ha, representing about 73% reduction
Supraglacial Lake
- Surface area decreased from 16.50 ha to 12.47 ha, representing a 24.4% reduction
Fig 1. (Post-event assessment) – Sintaphu Tsho (Main Lake) – Suhora analysis on ICEYE image (October 30, 2026, at 16:50:32 UTC)
Suhora also conducted a decade-long assessment of the lake system using late-October satellite imagery from 2016 to 2026. The analysis highlighted contrasting trends in the two lakes prior to the GLOF event.
Ten-Year Assessment of Sintaphu Tsho and Supraglacial Lake (2016–2026):
Sintaphu Tsho (Main Lake)
- Stable for a decade: 23.33 ha in 2016 and 24.13 ha in 2026, an increase of just 3.4%.
- Peaked on 28 October 2026, the day before the outburst.
- After the GLOF it fell to 6.54 ha, down 73%. That is less than a third of its size at any point in the previous ten years.
Supraglacial Lake
- Grew steadily from 5.74 ha to 16.51 ha, an increase of 188%, nearly three times its 2016 size.
- It added about 1.1 ha every year, with no year of shrinkage.
- After the GLOF it fell to 12.47 ha, down 24%. That is still more than twice its 2016 size.
Image Credit: Suhora analysis on Planet image (Decadal surface area analysis) – Video attached*
Commenting on the assessment, Krishanu Acharya, CEO & Co-founder, Suhora Technologies said, “The findings highlight the importance of continuous monitoring of glacial lake systems and the role of satellite-based Earth observation in understanding changes across vulnerable Himalayan terrain. Timely access to such insights can support better awareness of evolving environmental risks and strengthen monitoring and preparedness across the region. At Suhora, we are transforming satellite observations into actionable geospatial intelligence for disaster risk monitoring and management. “
The assessment indicates that Sintaphu Tsho experienced the most significant water loss during the outburst, while the supraglacial lake, despite its post-event reduction, continues to remain substantially larger than its 2016 extent.
The analysis was conducted using Suhora’s SID platform, which automatically selects suitable satellite imagery based on prevailing weather conditions, enabling near-real-time monitoring of Himalayan glacial lakes even under cloudy conditions.
