US Winter River Hazards Revealed by Satellite

Dangerous changes to Alaska's frozen rivers during winter—including the appearance of hazardous sections of open water—can now be detected via satellite.

Researchers from the University of Alaska Fairbanks developed a new technology to detect open water zones when the state's rivers freeze over in the early winter. The classification system using synthetic-aperture radar (SAR) could also be used across the Arctic, where open water zones present the same hazard.

The idea is that this can then be used to create hazard maps for those traveling, as many Alaskans do in rural areas. The frozen rivers act as "ice highways" and many people travel across them to fish and hunt.

"With this ice classification, we're trying to distinguish between ice and open holes in the ice," remote sensing scientist Melanie Engram of the Water and Environmental Research Center at the UAF Institute of Northern Engineering, who led the research, said in a statement. "A lot of studies have been done, especially in Canada, looking at different types of ice. We didn't do that. We just went ice versus open water."

Open water zones can be highly dangerous. And as climate change continues to worsen, rivers are not freezing in the same way they used to. The study noted that arctic warming has caused later freezing, which is impacted rural winter river travel. This is causing open water zones in mid-winter, and an earlier break-up of ice.

Engram worked with colleagues to develop the river ice classification system from data across eight Alaska rivers. Their focus was on developing a method that would work across October until January, when the open water zones present a threat.