River ice breakup has been progressing across the state, and as expected it has been a relatively "dynamic" process with ice jams and flooding in a number of locations (notably McGrath and Manley Hot Springs). However, it could have been even worse: temperatures have been below normal this month, significantly so at times, and there hasn't been the kind of dramatic warm-up that might have created a more violent collision between rushing meltwater and ice jams.
Here are temperature anomaly plots from (top) Fairbanks and (bottom) the UAF/ACCAP statewide temperature index (click to enlarge). Every day so far this month has been cooler than normal by both measures.
The map below shows the latest breakup situation, with mostly open water now on the major interior rivers. A major exception is part of the lower Yukon, where flood watches have been hoisted downstream of an ice jam just upriver from Grayling. Apparently water is so backed up that flooding is occurring for 70 miles upstream of the jam, and when the jam releases there will be a rush of water and ice into communities downstream.
From the NWS river forecast center:
ALASKA SPRING BREAKUP SUMMARY NWS ALASKA PACIFIC RIVER FORECAST CENTER ANCHORAGE AK 500 PM AKDT WED MAY 18 2022 ..RECENT NOTABLE EVENTS OR FORECAST CHANGES: Current webcams show the breakup front on the Yukon is right at Grayling, with ice shifting in the river across from town this afternoon. Satellite imagery from yesterday showed a very large ice jam in place 7 miles upstream from Grayling, extending to around 25 miles upstream from the toe of the jam. This ice jam is causing water levels to rise overbank and inundate low lying areas nearly 70 miles upstream. Sheet ice is still in place from Grayling down to Russian Mission. Downriver communities can expect rapid rises in water levels and heavy runs of ice when this jam releases. Additonal ice jams could also form as the breakup front pushes into the stronger sheet ice downstream, thus a flood watch has been issued for Grayling to Russian Mission. Downstream from Mountain Village the river was mostly open. An ice jam released near Old Crow and water levels at the US-Canada border crested Tuesday. Rapid rises in water levels along with heavy runs of ice are expected along the upper Porcupine River. ..SPRING BREAKUP STATUS FOR ALASKA... Statewide, breakup this year has been largely dynamic with ice jams observed at Manley Hot Springs, McGrath, Sleetmute, Red Devil, Crooked Creek, Circle, and Galena so far. While Manley Hot Springs and McGrath suffered major flooding, the other ice jams created minor to moderate flooding due to the cooler than normal temperatures so far this May. Breakup is complete on the Kuskowkwim, Koyukuk and Middle and Upper Yukon Rivers. The lower Yukon River still has some areas of weak in- place ice and runs of ice with breakup still continuing on the lower Yukon River. The Kobuk, Buckland and rivers north of the Brooks Range are still ice covered.