Snow, showers and freezing rain. There is a bit of everything falling Tuesday and feeding the ominously rising creeks and rivers in many parts of Minnesota.

By the time the storm moves on Wednesday, the Twin Cities may have 1 to 5 inches of snow, with the highest amounts in the far northern and western suburbs. Look out for freezing rain and sleet, the National Weather Service added.

With just three hours' notice, state transportation officials announced Tuesday that they will test the raising and lowering of the Stillwater Lift Bridge in preparation for closing the bridge if there is flooding.

"It is possible" that the St. Croix River could rise enough to flood the bridge deck, said Beth Petrowske, a spokeswoman for the Minnesota Department of Transportation. Raising the deck would also prevent the bridge's motor from being washed out by floodwaters and damaged, Petrowske added.

Also in Stillwater, construction of an emergency levee -- stretching 2,100 feet -- will begin either Wednesday or Thursday "to hold back the rising water of the St. Croix River," said Police Chief John Gannaway. "Expect traffic delays, as there will be significant truck and heavy equipment [movement] in downtown Stillwater."

Testing will run from 1:15 to 3 p.m. and could mean 10-minute delays for motorists, the state Department of Transportation said. The lift portion of the bridge has not been raised since boating season ended last fall.

Scott County declared a state of emergency at its board of commissioners meeting Tuesday morning. The county has already experienced some early flood scares with an ice jam forming last week on Sand Creek. Earlier Wednesday, County Road 9 was closed a little earlier than planned, probably due to some of the water coming from behind a breaking ice jam in Henderson, said Jordan Police Chief Bob Malz said.

"It's just a day earlier. I think the ice jam had something to do with it," he said.

County Road 1 from Scott County into Sibley County at Blakely has closed, too.

There will probably be more road closings, said Chris Weldon, Scott County emergency management director. Hwy. 101, that connects Shakopee and Chanhassen, and Hwy. 41, which connects Jordan and Chaska, are also likely to close, Weldon said.

"With the way the water is rising, I'm pretty sure [Hwy. 101 and Hwy. 41] are going to close. I just don't know when," he said.

The National Weather Service has changed the flooding forecast from moderate to major severity for the Minnesota River near Jordan affecting Scott and Carver Counties.

In Ramsey County, officials are preparing for the Mississippi River to hit historic levels dating to the 1965 flooding.

"Every drop of water that falls is going some place; it's not going into the dirt," said Judson Freed, the county's emergency management and homeland security director. "In a place where there normally wouldn't be a flood, you can get a foot worth of water just like that."

Along the Mississippi near downtown St. Paul, city and county crews are building flood walls.

Elsewhere in the east metro, calls are going out for volunteers to help in the coming days with sandbagging efforts in Cottage Grove and Hastings.

Central Minnesota may get 8 to 12 inches of snow, and a blizzard warning is in place for Duluth, according to Star Tribune meteorologist Paul Douglas. Double-digit snowfall is also possible in and around Brainerd, Hinckley and Mille Lacs.

Some of the heaviest amounts of overnight rain reported by volunteer observers were in areas of southwestern Minnesota, which has been the state's deepest and most saturated snow.

In Renville County, 1.15 inches had fallen at Danube by 5 a.m., with .83 at Marshall and .88 at New Ulm. In Carver County, in the southwest metro along the Minnesota River, nearly a half-inch fell by 6 a.m.

Road conditions north of the Twin Cities were icy and hazardous Tuesday morning, with a number of cars sliding into the ditch.

On Interstate Hwy. 35 near North Branch, freezing rain and slush made for slippery conditions, and traffic speeds slowed to 30 to 40 miles per hour.

At least three cars were spotted in the ditch near North Branch around 8:45 a.m., and traffic backed up in some spots.

While snow will blanket central and northern Minnesota, to the south, rain totals could run from 1 to 1.5 inches, the NWS added.

"This liquid moisture will lead to additional runoff and exacerbate the current flood situation," the NWS said in its latest hazardous weather alert.

Star Tribune staff writers Rochelle Olson, Bill McAuliffe, Jim Anderson, Joy Powell and Nicole Norfleet contributed to this report.

Paul Walsh • 612-673-4482