CHICAGO (AP) -- Rain and rapidly rising temperatures accompanied by thick fog threatened to cause flooding Saturday in the Midwest after days of Arctic cold, heavy snow and ice.
Thick ice on roads that contributed to dozens of deaths had thawed and mountains of snow turned into pools and streams of water.
The National Weather Service posted flood watches and warnings Saturday for parts of Illinois, Iowa, Wisconsin, Indiana, Michigan and Missouri. As much as 2 inches of rain fell in two hours during the night in west-central Illinois, the National Weather Service reported Saturday.
After subzero temperatures in places earlier in the week, Saturday morning readings were in the 40s as far north as Cheboygan, Mich., at the top of the state's Lower Peninsula, the weather service said. However, up to 7 inches of snow is possible in the state Sunday, the agency said.
The weather service said the Chariton River was overflowing and causing minor flooding in Chariton, Iowa. Flood stage is 15 feet; the river was at 16.6 feet at 3 a.m. Saturday and expected to rise a bit more. It said road flooding was reported in parts of Missouri.
Hundreds of people spent the night at Chicago's Midway Airport, where all 82 flights Friday evening were canceled as the thick fog rolled in. There were also more than 400 flight cancelations at O'Hare International Airport, the nation's second busiest.
Operations returned to near normal Saturday at Midway, although 36 flights were canceled because aircraft were out of position following Friday's weather problems. More than 100 flights were called off Saturday at O'Hare.
Temperatures also were rising in the Pacific Northwest, which has been pummeled by deep snow.
In Portland a couple inches of rain through Saturday was expected to wash away much of the 19 inches of snow that by one measurement had made December the city's snowiest month since January 1950.
"Once we start to see rain, it'll really melt down," weather service meteorologist Charles Dalton said. "It would be a good wager to say it's going to be gone by the end of the weekend."
In Seattle, meteorologist Johnny Burg was optimistic there wouldn't be any major flooding in Western Washington Saturday despite warming temperatures and melting snow that feel in the week before Christmas Day.
In Eastern Washington, 4 to 7 inches of new snow fell overnight in the Spokane area, where it began snowing a week before Christmas.
Slippery roads and cold have been blamed for at least 44 deaths this week: 11 in Indiana; eight in Wisconsin; five each in Ohio and Michigan; four each in Kentucky and Missouri; two in Kansas; and one apiece in Illinois, Oklahoma, Iowa, Massachusetts and West Virginia.