Sentinel-1 captured a 76-square-kilometre break from Petermann glacier. As western US snow cover fell to one fifth of normal, satellite measurements began feeding two-hour Cowlitz river forecasts.
Copernicus Sentinel-1 radar saw deterioration begin on 3 August in the floating tongue of Petermann glacier in northwest Greenland; the 76-square-kilometre slab broke away on 4 August. ESA describes the ice, up to 150 m thick in places, as Petermann's largest loss since 2012 and the Arctic's largest calving since 2020. The imagery also revealed how the fracture progressed across the tongue before the slab entered open water.[1]
Analysis by the Canadian Ice Service and the universities of Ottawa, Stirling, Leeds and Lancaster reports that two more sections of the floating tongue, about 97 and 87 square kilometres, are primed to break away. Adam Garbo of the University of Ottawa says the team had anticipated the completed separation for years. ESA's ARCTEX project within FutureEO follows such fractures and changes in the tongue's shape through regular satellite imagery. Cracks around both remaining sections are visible in the latest images.[1]
Across the western US, MODIS and VIIRS measurements showed snow cover holding between 20 per cent and 50 per cent of normal during the 2025-26 winter. January, February and March brought the lowest cover since the MODIS series began in 2001, while the highest daily inflow in April-June was also among the lowest measured. Upstream Tech's HydroForecast combines weather forecasts and river gauges with NASA snow and vegetation data to refresh Cowlitz river flow calculations every two hours. Tacoma Power uses those calculations in a system serving more than 151,000 homes.[2]
