Using the Regional Snowfall Index to Evaluate the “Great Blizzard of 1978”
The “Great Blizzard of 1978” struck the Upper Midwest and Ohio Valley regions of the United States on January 23–28, 1978. The blizzard produced the second lowest atmospheric pressure ever recorded over the contiguous United States from a non-tropical storm system. It is still the strongest storm to affect the Upper Midwest region since 1900 as measured by the Regional Snowfall Index (RSI).
The “Great Blizzard of 1978,” classified as a Category 5, or extreme storm, by the Regional Snowfall Index, struck the Upper Midwest region with force. Researchers classified the storm as a Category 3, or a major storm, when it affected the Ohio Valley region. Indiana, Ohio, and Michigan all declared states of emergency and had widespread travel cessation. South Bend, Indiana, picked up three feet of snow and many parts of southern Michigan accumulated over two feet of snow. Wind gusts up to 55 mph accompanied heavy snow, resulting in 10–20 foot snowdrifts across the regions, forcing many cities to shut completely down. Snow from this storm continued to blanket the regions for two months.
The RSI helps improve public understanding about the impacts associated with snowstorms, like the “Great Blizzard of 1978,” across the United States. It produces separate indices for six regions in the eastern two-thirds of the nation, ranking snowstorm impacts on a scale from 1 to 5. These ranks are based on the snowfall amount within the region’s borders, the spatial extent of the storm, and the relationship of these elements to the area’s population. This allows NCDC to account for both regional variation in snowfall patterns and how the amount of snow disrupts areas of the country differently.
The RSI is an evolution of the popular Northeast Snowfall Impact Scale (NESIS). NCDC has used NESIS since 2006 to provide a measure of the impact of Northeast storms, recording snowfall throughout the entire life of a storm.
NCDC has analyzed and assigned RSI values for almost 600 storms going as far back as 1900, with new storms added each year shortly after they occur. The snowstorm with the highest RSI value in each region is:
Northeast (ME, NH, VT, MA, RI, CT, NY, NJ, PA, DE, MD): February 21–27, 1969. About two million people over 16,000 square miles experienced over 30 inches of snowfall, which is twice the number of people affected and five times the amount of snow accumulated compared to any other snowstorm.
Ohio Valley (WV, OH, IN, IL, KY, TN, MO): November 21–29, 1950. A band of 20–30 inches of snow fell in Ohio and West Virginia, where 160 people died due to the storm.
Southeast (VA, NC, SC, GA, AL, FL): January 5–8, 1996. The “Blizzard of 1996” caused over $3 billion in damage and 154 deaths.
Upper Midwest (MI, WI, MN, IA): January 22–27, 1978. The “Great Blizzard of 1978” dropped more than two feet of snow over portions of Michigan, and 55-mph winds resulted in 10–20 foot snowdrifts.
South (MS, LA, AR, KS, OK, TX): February 17–21, 1921. One to two feet of snow fell in a band from southwest Oklahoma to northeast Arkansas.
Northern Rockies and Plains (ND, SD, NE, TM, WY): April 9–14, 1927. This late season storm dumped over two feet of snow in western Wyoming, the Nebraska panhandle, and the Black Hills of North Dakota.
Scientists from NCDC and Rutgers University have recently published a paper on this topic titled, “The Regional Snowfall Index,” which can be found in the December 2014 volume of the Bulletin of the American Meteorological Society.