More than 8,500 MidAmerican Energy customers were without electricity as of 4:30 p.m. Tuesday.
Illinois State Police were reporting that Interstate 74 south of the Big X interchange with I-80 was nearly impassable due to drifting and blowing snow.
The wind and snow is making the interstate extremely slick, according to state police, with visibility reduced to almost zero in places.
Illinois State Police Lt. Dylan Talbot said wind gusts are strong enough to cause vehicles to lose control and leave the roadway. Similar conditions are occurring on all north/south roads.
Motorists are urged to find alternate routes of travel and travel with caution, Talbot said.
At 1 p.m. Tuesday, MidAmerican's website reported about 2,000 customers were without electricity. By 2:45 p.m., that figure had lowered to around 1,200.
Then a wind-fed upsurge in outages occurred.
At 4:30 p.m., MidAmerican reported 2,788 customers in unincorporated Rock Island County were without power, while 1,917 customers in Rock Island were without electricity.
In Henry County, 511 customers were without power. Mercer County had 1,108 without power. Scott County had 201.
In Andalusia, 572 customers were without power. Outages in other communities included 562 in Milan, 346 in Matherville, 85 in Andover, 70 in Hampton, 45 in Rapids City and 265 in Reynolds.
Outages also were reported in Bettendorf, Davenport, LeClaire, Eldridge, Colona, Orion, Silvis and Sherrard.
Early Tuesday, MidAmerican announced it had activated crews from Iowa City, Waterloo and Des Moines to address the Quad-Cities area's ice storm Monday night and Tuesday morning, and to prepare for high winds expected Tuesday.
Ameren Illinois also reported thousands of customers were without power. Its online outage map included 2,157 in Aledo, 933 in Arpee, 1,099 in Viola, 492 in Sheffield, 224 in Woodhull and 175 in Mineral. Ameren outages also were reported in Kewanee, Neponset, Galva, Atkinson, Annawan, Cambridge, Ulah, Bishop Hill, Keithsburg and Alpha areas.