Glacier lake changes in Indian Central Himalaya from 1992-2023

The findings represent a multi-temporal glacial lake inventory of Indian Central Himalaya (ICH) derived from Landsat satellite imagery spanning more than three decades (1992–2023). The analysis utilizes Landsat-5 TM, Landsat-7 ETM+, and Landsat-8 OLI/TIRS sensors, all having a consistent spatial resolution of 30 m and 15 m, ensuring comparability across different time periods.
Satellite Data Characteristics
The selected images were acquired mainly during the post-monsoon and pre-winter months (September–November), which is optimal for glacial lake mapping in the Himalayan region due to minimal seasonal snow cover. Multiple scenes and paths were used for each period to ensure complete spatial coverage of the study area and to minimize cloud-related data gaps.
Temporal Evolution of Glacial Lakes
The temporal statistics indicate a consistent and significant increase in both the number and total area of glacial lakes over time:
During 1992–1994, a total of 187 lakes covering approximately 4.05 km² were mapped.
By 2001, the number increased to 231 lakes, with a total area of about 4.90 km².
In 2013, the inventory expanded further to 296 lakes occupying ~5.94 km².
The 2020–2021 period shows 318 lakes with a combined area of ~6.63 km².
The most recent dataset (2023) records 325 lakes covering approximately 7.48 km²
Key Trends and Implications
1. Lake Number Increase
The number of glacial lakes has increased by ~74% from the early 1990s to 2023, indicating widespread formation of new lakes, likely due to glacier retreat and thinning.
2. Lake Area Expansion
The total lake area has increased by ~85%, suggesting not only the formation of new lakes but also significant expansion of existing lakes, which is a critical indicator of glacier mass loss.
3. Accelerated Growth in Recent Decades
The rate of increase is more pronounced after 2001, coinciding with periods of enhanced regional warming and accelerated glacier retreat reported across the Himalaya.
4. Hazard Perspective
The combined increase in lake number and area implies a rising potential for glacial lake outburst floods (GLOFs), particularly as larger and expanding lakes tend to store greater volumes of water.

Conclusion:
The dataset clearly demonstrates a progressive intensification of glacial lake development over the past three decades. The observed trends strongly reflect the impact of climate-driven glacier retreat and highlight the growing importance of continuous monitoring and hazard assessment of glacial lakes in the Himalayan region