27 October 2025
Recent M.S. student Matt Scragg (UAF, Earth System Science ‘25) just published his first science paper in the journal Water Resources Research unraveling the why, where, and how open leads form and persist in ice covered rivers. Frozen rivers provide important winter transportation routes in Alaska, but open water zones (OWZs) in ice-covered rivers can be dangerous and are not well understood. We studied a recurring OWZ on the Tanana River near Fairbanks. Using satellite images and radar data from 2014 to 2023, we found that an OWZ formed in 8 out of 10 years when an ice jam occurred at a narrow section of the river during freeze-up. In the other 2 years, the river partially froze downstream, and no OWZ appeared. We used modeling to study how ice jam locations and flow rates impact OWZ formation. Results showed that ice jams can cause fast and turbulent water that prevents ice formation. Long-term records revealed that river flow during freeze-up is increasing, which could lead to more OWZs in the future. We highlight how the river's shape, flow rate, and ice jams work together to create OWZs. Understanding these factors can help predict where OWZs might form, improving safety for winter travelers on Alaska's rivers. Matt’s next professional challenge is helping rural Alaskans find appropriate river settings for hydrokinetic power generation through work with AKDNR’s DGGS.
, , , , , & (2025). Analysis of a persistent early winter open water zone within the ice-covered Tanana river near Fairbanks, Alaska using field studies, remote sensing, and hydraulic modeling. Water Resources Research, 61, e2025WR039921. https://doi.org/10.1029/2025WR039921