Present and future spatiotemporal patterns of glacier change across Alaska

Mountain glaciers affect water resources, natural hazards, sea-level rise, and more. Snowlines and melt extents are surrogate measurements of glacier mass balance that improve our understanding of glacier changes and help constrain models. Sentinel-1 synthetic aperture radar (SAR) provides reliable data every 12 days since ~2016 regardless of cloud coverage or daylight. We present a framework to derive glacier melt extents and transient snowlines from SAR data and demonstrate its utility for 99% of glaciers with an area of at least 2 km² in Alaska, representing over 85% of the total glaciated area in Alaska. We subsequently leverage these observations as calibration data for the  large-scale Python Glacier Evolution Model (PyGEM) and quantify changes in mass and equilibrium line altitude through the end of the 21st century for various emissions scenarios. We highlight stark spatial and temporal patterns in melt across and within various subregions in the observational dataset, as well as long-term trends revealed via modeling. All of our results are produced via an automated workflow that can easily be applied to other regions across the world.