It was another extremely cold weekend in the northern Plains and upper Midwest. Temperatures dipped into the single digits — at times below zero — for millions. The wind chill hit minus-40.
Chicago’s winter nickname was out again — “Chiberia,” with roots to the 2014 polar vortex cold outbreak. Photographer Barry Butler described his photo as a “Chiberian River Jigsaw Puzzle” given that the partially frozen Chicago River looked more like a delicate mosaic than a flowing body of water.
This photo caught my eye because it got me wondering — how often does the Chicago River freeze? Turns out, not that often, and there’s one reason: Lake Michigan, which feeds into the Chicago River. It’s large and deep and typically takes until mid-to-late January for ice to form. Until that happens, the relatively warm lake water (currently in the mid-40s at the center of the lake, but closer to freezing near the Chicago lakeshore) keeps the Chicago River ice-free.
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The latest cold outbreak, however, allowed for an increase of ice cover across all of the Great Lakes. Last week total ice cover was just 2.6 percent. Now it’s 13.3 percent. Lake Michigan specifically has ice cover of around 15 percent, with most of the ice hugging the lakeshores of Indiana, Wisconsin, Michigan and Illinois, including along Chicago’s lakeshore. The colder Lake Michigan can get during a given winter, the more likely the Chicago River is to freeze.
The recent cold outbreak contributed to what has been a very cold start to 2017 for the northern part of the United States (stats courtesy of the NWS):
- Billings, Mont.: For the first seven days in January, the average temperature at the Billings airport was nearly 23 degrees below normal.
- The first week of January was the coldest in seven years (since 2010), with average temp of 12.8 degrees at Grand Island and 12.9 degrees at Hastings
- Sidney, Mont., is on pace for the seventh coldest meteorological winter on record. Coldest since 1979!
- Glendive, Mont., is on pace for the fourth coldest meteorological winter on record. Coldest since 1979!
Now, this weekend cold outbreak wasn’t just confined to the northern Plains and Upper Midwest. The bitter cold Siberian air surged far enough south to bring below-freezing temperatures all the way to the Gulf Coast, where fountains froze in Pensacola, Fla. That’s some impressive cold. At the outbreak’s coldest, 92 percent of the lower-48 was below freezing. Even large southern cities like Raleigh and Memphis couldn’t escape the cold. Raleigh spend 84 straight hours below freezing, and Memphis 88 hours.
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Temperatures have warmed all week for the eastern half of the country out ahead of the next winter storm, which promises to bring a potentially crippling ice storm to a large area of the Plains. Many locations will go from record warmth to an ice storm in a matter of days. Even Chicago, after seeing a low of zero last Saturday, rebounded to a high of 51 by Tuesday afternoon, but the forecast calls for snow, sleet and even freezing rain by the end of the upcoming week.
One thing’s for sure. The revolving door of arctic outbreaks and winter storms reminds us that while we’re in the thick of the winter season, the days are getting longer, which means spring will be here before we know it!
Weather is awesome. #cwgpicoftheweek
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