December storm ranked among five worst of decade
The big December storm that dropped a record 21.1 inches of snow on Baltimore has been ranked among the five worst of the decade in terms of its impact on the Northeast.
The National Oceanic and Atmospheric Administration has given the snowstorm a rating of 3 ("Major") on its Northeast Snowstorm Impact Scale (NESIS). It is now the smallest Cat. 3 storm of the 12 on record.
The NESIS system was developed in 2004 to provide a systematic way for meteorologists (and the rest of us) to compare Northeast snowstorms. The system generates an index number based on snow depth (at least 10 inches), geographic expanse and the size of the affected population. Rankings range from Cat. 5 ("Extreme") to Cat. 1 "Notable").
NOAA found that the December storm, which dumped top-ten snow on Baltimore, Washington and Philadelphia, was not an especially large storm, and did not have much impact on big population centers in New York and Boston. So, it got a 3 on the NESIS scale.
Even so, only four other storms in the past decade have ranked that high or higher. They include storms in December 2002 (Category 3); February 2003 (Category 4); January 2005 (Category 4); February 2006 (Category 3) and February 2007 (Category 3).
The highest-impact storms on the NESIS scale - and the only ones to get a Cat. 5 - are the “Superstorm” on March 1993 followed by the “Blizzard of ’96” in January 1996. The scale was developed in 2004, and ranks Northeast storms dating back to 1888.