Winter's Grip, Followed By Thaw, Equals Fog

Widespread fog has gripped much of the nation's center these past few days. Roughly along the Interstate 35 corridor from north of Dallas, through Kansas City and into southern Minnesota.

For several days now, this part of the country has been in the midst of a tight winter grip, with above average snowfall and below average temperatures.

Now, the region is warming up - and as the warm air moves over the cold snow pack and terrain, and it created several mornings with thick, dense fog.

In east-central Kansas, the fog caused a 40-car accident on I-35 that killed at least one and caused dozens of injuries.