The snow covering streets and sidewalks this morning will grow deeper and deeper over the next two days, challenging local officials as to just when to declare a snow emergency and deploy their armada of plows.

As of 6 a.m. today, few official snow amounts had been reported, but among them: 5 inches in Benson, 4.5 inches in Granite Falls, 3 inches in Madison,  2.8 inches in Albany and 2 inches in Winthrop.

Traffic in the Twin Cities was mostly flowing smoothly at 6 a.m. But a rollover accident was blocking traffic in Interstate Hwy. 94 at Cedar Avenue and a spinout was blocking lanes on southbound Hwy. 169 at Rockford Road.

The Minnesota Department of Transportation this morning reported hazardous driving conditions on most roads west and south of the Twin Cities including Hwys. 12 and 7, U.S. Hwys. 212 and 14 as far out as Redwood Falls and Renville.  Difficult driving conditions persist across the entire southeastern part of the state.

Only a few inches of snow fell overnight Sunday, but plow managers like Mike Kennedy of Minneapolis were already looking ahead to the 8 to 10 inches expected by Tuesday afternoon.

Act too soon and a second, confusing snow emergency might be needed to clear streets. Wait too long and packed-down snow might stick around until spring.

"It's difficult when it comes in over several days," Kennedy, the Minneapolis director of Public Works, said Sunday. "It would be easier if it came in one day and that was it. You don't know exactly when to declare a snow emergency."

More snow fell overnight in western Minnesota, causing local officials to delay or cancel school Monday and offering a sneak preview of the weather headed toward the Twin Cities.

Weather problems also forced flight cancellations Sunday at Minneapolis-St. Paul International Airport, and plans are already in place to handle hundreds of stranded passengers Monday if the weather worsens.

For Kennedy and other emergency planners, this storm has a whiff of the familiar. "We had the same forecast at Christmas," he recalled.

That storm was expected to produce double-digit snowfalls but fizzled out after one day.

This time, the storm's challenges are expected to increase Monday and continue to Tuesday, with snow totals rising to about 10 inches in the Twin Cities metro area.

In fact, some forecasts Sunday estimated that in some places, such as western Minnesota, there could be as much as 14 inches. Or not.

"You're at the whim of the forecasters," Kennedy said.

Also scrambling will be airlines and airport workers, already struggling to recover after a weekend of numerous canceled flights because of a heavy snowstorm on the East Coast that dumped nearly 2 feet of snow in the Washington area.

Metropolitan Airports Commission spokesman Pat Hogan said the airport is preparing for more possible delays from the local storm. Employees are on-call for snow cleanup, and about 700 cots are available at the airport if travelers need to spend the night, Hogan said.

"We're just in a waiting game, waiting for the snow to hit this area," Hogan said Sunday night. "We should be OK. There likely will be some [flight] delays along the way."

Nationally, Delta Air Lines canceled hundreds of flights over the weekend because of the snow that crippled airports in the mid-Atlantic region. Nearly all Delta flights from the Minneapolis-St. Paul International Airport bound for Washington, Baltimore, Philadelphia and Pittsburgh were canceled Sunday.

Delta made the call midday Saturday to cancel the Sunday flights, Delta spokeswoman Chris Kelly said. That should have been enough time to notify affected travelers and to prevent them from arriving at airports Sunday, she said.

Delta plans to resume flights to the region Monday, but there will be only a limited number of flights because of the backlog of travelers and ongoing weather issues.

In addition to the large snowfall, part of the challenge was that many mid-Atlantic airports are not equipped to deal with so much snowfall, she said.

Kelly and Hogan recommend that travelers check their flights Monday before arriving at airports. "The best thing we can all do to help each other out is to check flights online before we go to the airport," Kelly said.

Heron Marquez Estrada • 612-673-4280