FAIRBANKS — The National Weather Service warned of thin river ice this week, especially on the Steese Highway near downtown Fairbanks.
The downtown-area ice thickness number is especially important because this part of the river gets heavy traffic in the springtime, with several events that take place on the river ice. The first is the Yukon Quest International Sled Dog Race, in which the first dog teams of the 2019 race are expected to arrive early next week.
The Weather Service took no ice thickness measurement for the Chena River near the Steese Highway when collecting February ice thickness data Friday because the ice conditions made it too dangerous to measure the ice, said Weather Service hydrologist Karen Endres in an email.
The Weather Service tries to measure and report on ice thickness conditions monthly at more than a dozen lakes and rivers around the Interior. Ice conditions can vary wildly by location.
Friday’s numbers for early February generally showed thinner-than-average ice formation, although ice thickness was slightly above average at locations including the Chena River downstream of Fairbanks at Pike’s Landing. That location measured 22 inches this year, compared with 18 inches on average for early February.
In an email announcing the February ice measurements, Endres warned of particularly dangerous conditions on rivers.
“I have also spoken to several knowledgeable people that have all said that the rivers are very dangerous this year,” she wrote. “There are lots of open areas, ice shelf break downs and weak ice.”
Endres said she had heard that river conditions were particularly bad on the Chena River near the Moose Creek Dam.
At the Steese Highway Bridge near downtown Fairbanks, Endres said it’s unusual although not unprecedented for an early February ice measurement to be skipped because of safety concerns. On an average year — calculated from 17 years of measurement data — the ice measures more than 2 feet by early February.
The Weather Service didn’t take January measurements last month because of the partial government shutdown.
River ice is less stable than lake ice and is harder to predict. Lake ice thickness generally relates to temperature and snow cover, Endres said. With rivers, the flow rate of the water also affects ice formation.
“In some cases where it has broken down on the edges, it could be that there was a high flow when it froze and now there’s a very low flow and the ice was not thick enough to support it, so it just collapsed in,” she said. “Once it collapses in, the refreezing is never as strong as the initial ice would have been.”
As of Monday, no changes had been planned to the Yukon Quest finish because of river ice conditions in Fairbanks, although race spokeswoman Pixie Ingram said race officials and trailbreakers were keeping a close watch on conditions.
Contact Outdoors Editor Sam Friedman at 459-7545. Follow him on Twitter: @FDNMoutdoors
National Weather Service ice thickness measurements taken Friday
Birch Lake — 33 inches
Salcha River at Richardson Highway — 25 inches
Chena Lakes — 25 inches
Twin Bears Camp — 25 inches
Olnes Pond — 12 inches
Smith Lake (University of Alaska Fairbanks
campus) — 21 inches
Tanana River at Chena Pump Road — 14 inches
Chena River at Pike’s Landing — 22 inches
Chena River at Steese Highway — Not measured due to unsafe ice conditions
Quartz Lake — 32 inches
For more information about river and lake ice thickness, go to weather.gov/aprfc/IceThickness.