【Schoolmistress 2】

A severe ice storm threatens to plunge millions of Americans into darkness and Schoolmistress 2paralyze travelers from Oklahoma to Washington, D.C. through the weekend. In some areas, at least an inch of ice could coat everything from tree limbs to roadways, downing power lines and causing surreal scenes of destruction.

The storm system responsible for the freezing rain, which is liquid precipitation that freezes upon contact with a surface, will vault copious amounts of moisture into a bitterly cold air mass already in place across much of the Central U.S., Midwest and Mid-Atlantic states.

This will set up heavy precipitation, with snow in areas that have the deepest layer of cold air, and sleet and freezing rain where the wedge of cold air is more shallow, with above freezing air temperatures aloft.

Freezing rain occurs when a layer of warm air comes between two layers of cold air, like an unwelcome third wheel on a date.

The warm air causes falling snow to turn to rain, and the shallow layer of cold air hugging the surface (cold air is denser than warm air) causes the rain to hit the ground and freeze almost instantly.

This ice storm will not be your ordinary, "Hey, look at those pretty, ice-covered trees" event. Instead, if current projections pan out, it will be a crippling event for millions, with power knocked out for days and travel all but impossible.

States of emergency are in effect for Oklahoma, Missouri and other areas as officials brace for the onslaught of winter weather.

The region that is expected to get the greatest ice accumulations, with widespread amounts of a half-inch or more, will span from northwestern Texas into western Oklahoma and northwestern Kansas. This is where the combination of moisture and low level cold air will be maximized.

The ice storm will hit cities including Topeka, Oklahoma City, St. Louis, Kansas City, Columbus, Pittsburgh and, eventually, Washington, D.C.

However, the ice accumulations in the Mid-Atlantic are not expected to be significant enough to cause major problems.

An event of this magnitude, across such a large area, is not a typical annual event. Instead, USA Todayreported this may be on the order of a once-in-a-decade storm.