Late Season Northeast Snowfalls: The Climatology Behind Them

April 11, 2023 // Article by: Steven Weinstein

After a major Nor'Easter on March 13 - 15th, 2023 that buried parts of the Catskill and Berkshire mountains in New England with more than 2 feet of snow, it had us wondering, just how common are late season snowfalls across the Northeast? Today we take a deeper dive into the climatology behind late season snowfall events in various cities across the Northeast and we look back at some of these infamous events that have impacted the Northeast throughout recorded history. 

As a rule of thumb, larger snowstorms are much harder to come by across the Northeast into late March and especially into April. While there is generally less cold air to work with at this point in the season to get the job done (particularly across the Mid-Atlantic), the higher sun angle also comes into play towards and past the Spring Equinox. These factors in conjunction with a system's daytime arrival naturally makes any snow that is able to fall much harder to stick, especially on roadways and parking lots. Therefore, for one of these late season systems to pan out and produce significant snowfall, it generally takes a nighttime arrival and a lot of cold air to work with, and although such events are less common, they do happen. 

Taking a closer look at snowfall cimatology across some Northeast cities reveals a rather intuitive trend: the further north you go, the longer the winter season. This is easily seen in the graphic below where the average latest measurable snow for areas south of the Mason-Dixon line is late February, while it's early to mid March for NJ and PA. New England's snow potential is extended the longest, with the average latest snowfall across cities such as Hartford and Boston occurring in late March. However, when taking a look at the latest measurable snowfalls on record, these cities can see minor snow events well into April and for New England, even May!

While smaller storms are the norm, significant to even major snowfall events really aren't all that rare across the Northeast during March and April. Major Northeast blizzards occurring in March have been dated back to the 1800s with a March 11th - 14th storm in 1888 known appropriately as the "Great Blizzard of 1888." This event was one of the more destructive and deadly snowstorms in U.S. history that dropped 20 - 40 inches of snow across parts of New England and the Mid-Atlantic. Next, was an event that occurred on April 3-4th, 1915, which buried many Northeastern cities with over a foot of snow. Remarkably, much of this snowfall was able to stick during the daytime, even in cities such as Philadelphia and New York, which was a testament to the unbelievably heavy nature of the snow. Additionally, this stands as the only year where April was the snowiest month of the "winter" season for Central Park, NY, due in large part to the April 3-4th event.

Perhaps one of the most famous storms was on March 12th - 14th, 1993, known as the "Storm of the Century." This monster of a storm brought blizzard like conditions, coastal flooding, and hurricane force winds to much of the Eastern Seaboard, with major snowfall of 1-2+ feet stretching from Northern Alabama and Georgia all the way up through Maine. Across the U.S., millions of power outages and hundreds of fatalities resulted from this event. Furthermore, this nor'easter was given the highest ever Northeast Snowfall Impact Scale (NESIS) rating in recorded history. Similar to hurricane rankings, the NESIS scale ranges from Category 1 (notable impact) to a Category 5 (extreme impact) storm, with NESIS rankings being a direct function of three variables; the area affected by the storm, the amount of snow, and the number of people living in the storm's path (NOAA). This particular storm was given a Category 5 rating with a NESIS score of a 13.20.

Snowfall totals from the 1993 "Storm of the Century." Source: NOAA and NCEI

Other such late season events have included the "April Fool's Day Blizzard" that occurred on March 30th - April 1st, 1997 which was no joke, hitting New England the hardest where a widespread 1-2+ feet of snow fell, and even Boston recording around 25 inches. The storm was given a NESIS Category 2 rating. Another Category 2 in April occured on April 6-7th,1982 and dropped 4 to 10 inches across much of the Northeast, with 10 - 20 inches accumulating across parts of the Poconos, Catskills, and Berkshires. Astoundingly, even a May snowstorm isn't out of the question as those in Northern New England found out when a system on May 9th - 10th in 1977 dropped over a foot of snow across the higher hills of Worcester County in Massachusetts as well as across the Catskills and Berkshires. More recently, the Northeast was impacted by an onslaught of four March Nor'Easters in 2018, which occurred on the 1st-3rd, the 6th-8th, the 12th-14th, and the 20th-22nd respectively. Two of which were given a Category 2 ranking on the NESIS scale! All of these storms packed punch, bringing swaths of heavy snow, high winds, and coastal flooding to portions of the Mid-Altlantic and New England. 

While April showers generally bring May flowers, sometimes Mother Nature has other ideas!