• Energy Research

Abstract We analyze changes in the maximum annual transient snowline elevation (MATSL) of glaciers for two regions in western North America from 1984 to 2024 using five satellite remote sensing datasets. MATSL reached its highest elevations in 2019 (155 m above the long-term average) for Alaska (Region 1) and in 2023 (148 m) for Western Canada and USA (Region 2). The rate of MATSL rise accelerated fourfold, increasing from 2.1 ± 0.8 m a−1 in 1984–2010 (r 2 = 0.1, p < 0.01) to 8.9 ± 1.7 m a−1 in 2010–2024 (r 2 = 0.5, p < 0.01). In 2019, 91 glaciers exceeded the 95th percentile MATSL elevation, a threshold indicative of complete loss of the accumulation area, in Region 1. In Region 2, 149 glaciers exceeded this threshold in 2023. Year-to-year variability in MATSL was strongly influenced by mean summer air temperature with sensitivities of +46 m °C−1 (r 2 = 0.54) and +23 m °C−1 (r 2 = 0.30) for Regions 1 and 2, respectively. Mean spring snow water equivalent also played an important role with sensitivities of −351 mm w.e.−1 (r 2 = 0.48) and −155 mm w.e.−1 (r 2 = 0.37), respectively. Per-glacier analysis revealed that south-facing slopes experienced the largest MATSL increases. Terrain attributes, including slope, aspect, hypsometry, and elevation, enhanced MATSL prediction models compared to those using only climate variables. The pronounced rise in MATSL underscores a critical glacier melt feedback mechanism, warranting further investigation. This study highlights the utility of automated MATSL time-series mapping for regional-scale analyses and identifies key limitations and opportunities for future research.

Abstract We analyze changes in the maximum annual transient snowline elevation (MATSL) of glaciers for two regions in western North America from 1984 to 2024 using five satellite remote sensing datasets. MATSL reached its highest elevations in 2019 (155 m above the long-term average) for Alaska (Region 1) and in 2023 (148 m) for Western Canada and USA (Region 2). The rate of MATSL rise accelerated fourfold, increasing from 2.1 ± 0.8 m a−1 in 1984–2010 (r 2 = 0.1, p < 0.01) to 8.9 ± 1.7 m a−1 in 2010–2024 (r 2 = 0.5, p < 0.01). In 2019, 91 glaciers exceeded the 95th percentile MATSL elevation, a threshold indicative of complete loss of the accumulation area, in Region 1. In Region 2, 149 glaciers exceeded this threshold in 2023. Year-to-year variability in MATSL was strongly influenced by mean summer air temperature with sensitivities of +46 m °C−1 (r 2 = 0.54) and +23 m °C−1 (r 2 = 0.30) for Regions 1 and 2, respectively. Mean spring snow water equivalent also played an important role with sensitivities of −351 mm w.e.−1 (r 2 = 0.48) and −155 mm w.e.−1 (r 2 = 0.37), respectively. Per-glacier analysis revealed that south-facing slopes experienced the largest MATSL increases. Terrain attributes, including slope, aspect, hypsometry, and elevation, enhanced MATSL prediction models compared to those using only climate variables. The pronounced rise in MATSL underscores a critical glacier melt feedback mechanism, warranting further investigation. This study highlights the utility of automated MATSL time-series mapping for regional-scale analyses and identifies key limitations and opportunities for future research.

Les glaciers sont des éléments essentiels du paysage montagneux, revêtant une grande valeur culturelle et touristique, et ils fournissent de l'eau fraîche et abondante à de nombreux cours d'eau d'amont à la fin de l'été et pendant les années de sécheresse. Nous rendons compte des taux de perte de masse dans l'ouest du Canada et dans les glaciers américains limitrophes. Au cours de la période 2021-2024, les glaciers des deux régions ont connu un doublement de leur taux de fonte par rapport à la décennie précédente. Les glaciers ont perdu 12 % de leur volume total en 2020 au cours de cette période de quatre ans. Les conditions qui ont favorisé une forte perte de masse comprenaient des conditions chaudes et sèches et un assombrissement de la surface de la neige et de la glace. Glaciers are essential parts of the mountain landscape, with strong cultural and tourism value, and they provide cool, plentiful water to many headwater streams during late summer and years of drought. We report on rates of mass loss for western Canada and the conterminous US glaciers. Over the period 2021-2024, glaciers in both regions experienced a doubling of melt rates compared to the previous decade. Glaciers lost 12% of their total 2020 volume over this four-year period. Conditions that favored strong mass loss included warm dry conditions and surface darkening of snow and ice.

Les glaciers sont des éléments essentiels du paysage montagneux, revêtant une grande valeur culturelle et touristique, et ils fournissent de l'eau fraîche et abondante à de nombreux cours d'eau d'amont à la fin de l'été et pendant les années de sécheresse. Nous rendons compte des taux de perte de masse dans l'ouest du Canada et dans les glaciers américains limitrophes. Au cours de la période 2021-2024, les glaciers des deux régions ont connu un doublement de leur taux de fonte par rapport à la décennie précédente. Les glaciers ont perdu 12 % de leur volume total en 2020 au cours de cette période de quatre ans. Les conditions qui ont favorisé une forte perte de masse comprenaient des conditions chaudes et sèches et un assombrissement de la surface de la neige et de la glace. Glaciers are essential parts of the mountain landscape, with strong cultural and tourism value, and they provide cool, plentiful water to many headwater streams during late summer and years of drought. We report on rates of mass loss for western Canada and the conterminous US glaciers. Over the period 2021-2024, glaciers in both regions experienced a doubling of melt rates compared to the previous decade. Glaciers lost 12% of their total 2020 volume over this four-year period. Conditions that favored strong mass loss included warm dry conditions and surface darkening of snow and ice.

Knowledge about the long-term response of High Mountain Asia (HMA) glaciers to climatic variations is paramount because of their important role in sustaining Asian river flow. Here. a satellite-based time series of glacier mass balance for seven climatically different regions across HMA since the 1960s were estimated by DEM differencing of multi-temporal optical data. The DEMs were corrected for planimetric and altimetric shifts using SRTM as a reference. Elevation dependent biases, present due to the tilt between two DEMs, were also estimated for each DEM using two-dimensional first order polynomial trend surfaces relative to the SRTM DEM. To remove outliers, we analyzed individual glacier elevation differences for each 100 m altitude bin. Considering the heterogeneity of the thickness change in glacierized terrain, outliers were removed by using an elevation dependent sigmoid function. Our study reveals a constant mass loss in all regions even in regions where glaciers were previously in balance with climate.

Knowledge about the long-term response of High Mountain Asia (HMA) glaciers to climatic variations is paramount because of their important role in sustaining Asian river flow. Here. a satellite-based time series of glacier mass balance for seven climatically different regions across HMA since the 1960s were estimated by DEM differencing of multi-temporal optical data. The DEMs were corrected for planimetric and altimetric shifts using SRTM as a reference. Elevation dependent biases, present due to the tilt between two DEMs, were also estimated for each DEM using two-dimensional first order polynomial trend surfaces relative to the SRTM DEM. To remove outliers, we analyzed individual glacier elevation differences for each 100 m altitude bin. Considering the heterogeneity of the thickness change in glacierized terrain, outliers were removed by using an elevation dependent sigmoid function. Our study reveals a constant mass loss in all regions even in regions where glaciers were previously in balance with climate.