we average around an inch of snow in April don't we? It's a once in decade event to get a decent April snowfall, so it's rare but not unique.
October 2011 was unique.
I think we've had one decent April snowfall in every decade I've been around.
I'm just going by JFK numbers (snowfalls of 4 inches or higher)
April 1982..... 8 inches
April 1996..... 4 inches
April 2003...... 6 inches
April 2018........ 6 inches