The fog around Wichita has arrived quietly enough — but it's not moving on.

Morning fog has become a staple of most of the past week, and forecasters say it will linger at least a bit longer.

"I think we'll have a tendency toward fog for at least the next seven days," said Mike Smith, president of WeatherData, the Wichita-based subsidiary of AccuWeather.

Freezing fog cloaked Wichita with hoarfrost last week and created black ice on stretches of I-35 near Wellsville on Saturday, triggering a number of multi-vehicle pileups.

A 3-year-old boy was killed and several other people were critically injured in a 30-car pileup near Wellsville.

"We've been plagued with dense fog the past several days," said Jim Caruso, a meteorologist with the National Weather Service in Wichita.

Humidity at ground level is high, he said, and as temperatures drop overnight the moisture condenses. When that happens, clouds form.

Fog is simply a cloud that has formed at ground level. The fog has occasionally been quite dense: Visibility was down to 100 feet or less at times on Monday in parts of Kansas.

Portions of seven states in the Great Plains were under dense fog advisories Monday, including the eastern half of Kansas.

A dense fog advisory is in effect until noon today for the Wichita region.

"Right now we're in the soup, and we're going to stay in the soup," KWCH's Mark Larson said.

That's because there's no wind or frontal boundary to stir things up and either move the moisture east or scour it out of the atmosphere in the form of a hearty rain, forecasters say.

"We're looking for a 'weather maker' " to come through the region and clear things out, Larson said.

That may arrive Wednesday, he said, when pieces of a major storm system now arriving on the West Coast make their way into the Great Plains.

But Smith said he has doubts those pieces will be strong enough to oust the fog once and for all.

"As long as we have this stagnant air and don't have a good storm or a strong cold front to push it out of here, we're going to have this tendency to get fog," Smith said.