The recent “Blizzard of 2015” shutdown several major metropolitan areas in the Northeast and left several locations across Connecticut, Maine, Massachusetts, New Hampshire, and New York covered in over two feet of snow. But, how did this snowstorm compare to the region’s most historic storms? To place this storm and its societal impacts into historical context, NCDC used the Regional Snowfall Index or RSI to rank it on a scale from 1 to 5—similar to the Fujita scale for tornadoes or the Saffir-Simpson scale for hurricanes. 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.
The RSI value for January 25–28, 2015, snowstorm is 6.16, which makes it a Category 3 or major event for the Northeast. With that RSI value, the snowstorm ranks 26th out of the 423 northeastern snowstorms NCDC has analyzed since 1900. The area of snowfall and population affected by 20 inches of snow or more were the primary drivers for this storm’s raw RSI score. Almost 5 million people experienced over 20 inches of snow and 15 million experienced over 10 inches of new snow. While these are significant impacts, the footprint of the heavy snow was relatively small compared to RSI Category 5 storms. These rare events typically have over 45 million people experiencing over 10 inches of snow. Nonetheless, this storm is well within the top 10% of storms analyzed for the Northeast.
The late February snowstorm of 1969 remains the strongest storm to hit the Northeast, with an RSI value of 34.03 making it a Category 5 or extreme event. The March 1993 “Storm of the Century” remains the second strongest snowstorm to hit the Northeast, with an RSI value of 22.12 also making it a Category 5 event.
Learn more about the Regional Snowfall Index and use our interactive mapping tool to see RSI rankings for almost 600 snowstorms since 1900.
Source: NOAA
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