The image above comes from a 2001 paper by Hirsch et al. (here in PDF) titled, An East Coast Winter Storm Climatology. The top curve shows all East Coast winter storms, and the bottom shows the most intense storms. for the period 1948 to 1997.
As the figure implies, they concluded in that analysis:
the frequency of ECWS show a downward tendency over the study period but at insignificant levels. One test found a decreasing trend in strong ECWS significant for an alpha = 0.10.
So there was no trend 1948 to 1997, or a slightly downward trend. This is interesting because over the latter half of that period one analysis (Willett et al. 2010) found an increase in the water content of the lower atmosphere over the US East Coast. So those who argue for a simple relationship between increasing water content of the atmosphere and storm strength, data do not support such a claim over this multi-decadal period, in this region.
In 2010 Frankoski and DeGaetano published an update to Hirsh et al. 2001, extending data through 2006. They concluded:
No significant time-dependent trends were identified for precipitation or snowfall from East Coast Winter Storms or for the percentage of precipitation or snowfall from East Coast Winter Storms.
Such research is likely why the IPCC AR5 concluded in 2013:
In summary, confidence in large scale changes in the intensity of extreme extra-tropical cyclones since 1900 is low.
What that means in climate-speak is that the detection of trends in winter storms has not been achieved. It also means that the IPCC has not attributed any trends to human influences. Detection and attribution are explained in some detail in my recent book.
You can of course find fringe views on both detection and attribution out there on the internet (carefully cherry picked). There are also plenty of smart folks trying to do their own analyses without referencing the IPCC or the peer reviewed literature on the subject. Minority views and amateurs are legitimate and worth hearing, as they can add valuable new perspectives. But if these folks really wanted to contribute to scientific understandings they should seek to publish their alternative theories in the peer reviewed literature.
No one – least of all those who consider themselves professional journalists – should confuse these alternative perspectives for what is found in the peer-reviewed literature and the assessments of the IPCC.