The average low in Seattle in February is 37 degrees, in New Jersey it's an average high of 40 and low of 21, the constant melting then freezing of ice is what does most of the damage here. From what I can find Seattle gets 3.9 days of snow per year on average, NJ gets 12.2 days of snow on average, but again it's really the bounce between above and below freezing that is what does the damage.

So it's very significant that we literally have 3 entire months where the daily average high is above 32 and the low is below 32, where as Seattle has exactly 0 months where the average low goes below 32.