Introduction

Residents of the Midwest who were hoping for a white Christmas were not disappointed by the record-breaking snowstorm that affected the Ohio River valley on December 22 and 23, 2004. In many parts of the region, it ranks as the worst winter storm on record. Hundreds of thousands were left without power and thousands were left stranded as airline, automobile and train traffic ground to a halt. In western Kentucky, a 29-mile traffic jam on Interstate 24 stranded nearly 1,000 people in their automobiles overnight. In an unusual occurrence, two freight trains were involved in a head-on collision in Crawford County, Kentucky, when one of the trains slid off the tracks. Insured property losses approached $230 million and the total financial impact of this extraordinary event has been estimated at $900 million. Tragically, seventeen people died in storm-related incidents.

The map below illustrates that while the Ohio Valley bore the brunt of the storm, its impact extended from Texas into southern Ontario, a distance of approximately 1,400 miles. The combination of snowfall accumulations of two feet or more and freezing rain delivered a devastating one-two punch to southern Illinois, southern Indiana, western Kentucky and nearly all of Ohio.

The storm accumulated a number of remarkable statistics:

• Washington County in southern Indiana experienced a snow accumulation of thirty-two inches.

• At the height of the storm on December 22nd, snowfall rates were nearly four inches an hour in southern Indiana.

• Nearly six inches of sleet fell in Henry County, Kentucky.

• In Ohio, an estimated 442,000 homes and businesses were left without electricity.

• The area covered by at least six inches of snow was nearly 160 miles wide and 860 miles long (137,600 square miles).

And, if snow and freezing rain weren't enough, the frigid arctic air mass that followed the storm sent temperatures plunging well below zero for several days, hampering cleanup efforts in these hard hit areas. Wind chill factors reached twenty-five degrees below zero.

Of the 156 catastrophic winter storms between 1949 and 2004, the December 2004 event ranks as the 32nd most damaging. The two-day snowstorm had such a profound impact that it was included in the National Climatic Data Center's Selected Global Significant Events for December 2004.

National Climatic Data Center (NCDC) chart of weather events during December 2004. Note the highlighting of the December 22-23 snowstorm.

The historic December 2004 snowstorm was the result of a unique combination of atmospheric conditions that merits further investigation.

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© 2005-2006 Mark A. Thornton