Ice Storm of December 12-13, 2000

This was a major ice storm for the affected areas because of widespread power outages due to trees falling on power lines.  Estimates are around 235,000 customers throughout the area lost power. Representatives of Southwestern Electric Company stated this was the worst ice storm in their history. Highways and roads mostly remained open even in the northern sections of the four-state region where there was some sleet accumulations.
 
What Is the Difference Between Freezing Rain, Sleet, and Snow?
The Wednesday 6 am sounding on December 13th 2000 at Shreveport indicated a melting layer between 3,000 and 11,300 feet with approximately 4,000 feet where temperatures were between 45 to 50 degrees Fahrenheit. The shallow freezing layer was from the surface to 3,000 feet with the coolest temperature at 2,100 feet at around 23 degrees Fahrenheit. This temperature profile of the atmosphere (sounding) caused the snowflakes to completely melt and then not have time to refreeze into sleet before reaching the ground. Further north, across the Red River Valley of Northeast Texas, Southeast Oklahoma, and Southwest Arkansas, the freezing layer at the surface was larger (more depth) so the liquid droplets had time to freeze into sleet.
Freezing Rain Sounding
The red line is a temperature profile through a portion of the atmosphere. In this example, the snowflakes completely melt and fall through a shallow freezing layer not allowing them to refreeze into sleet before reaching the ground. As a result when the liquid droplets encounter exposed objects they freeze upon contact.
 
Freezing rain occurs when rain falls through a shallow layer of freezing temperatures at the surface and freezes upon to form a coating of glaze upon the ground and on exposed objects, such as signs, trees, and power lines.

 
Sleet Sounding
The red line is a temperature profile through a portion of the atmosphere. In this example, the freezing layer at the surface is large enough to freeze completely melted snowflakes (rain) or to refreeze partially melted snowflakes.
Sleet is defined as generally transparent, globular, and solid grains of ice, which have formed from the freezing raindrops or the refreezing of largely melted snowflakes when falling through a below-freezing layer of air near the Earth's surface.
 
Snow Sounding
The red line is a temperature profile through a portion of the atmosphere. In this example, there is no melting layer so the snowflakes make it to the ground.

Snow is precipitation composed of white or translucent ice crystals, chiefly in complex branched hexgonal forms and often agglomerated into snowflakes.

 

 

   
Winter Storm Map
 

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