It's a fairly legitimate structure, of about 8 to nine feet in height. It was clearly built by students in their spare time, above Bass Library on the Cross Campus lawn in front of Sterling.
Snow structures are not new to New Haven. There are a number of other happenings, particularly the structure known as "SnowBama" that appeared as far back as 2014. And the trend continues into this year, with new edifices constructed in town, such as "Snow Buddha" (another David Sepulveda creation)
Aside from this winter being warm, towards the beginning, we did get a fair amount of icy precipitation in the month of February. California has received record amounts of precipitation.