it's because the public get's tired of skiing by the time spring rolls around.
it really sucks. last season my hill had a huge base and they closed it after the 2nd week of march because they couldn't make any money.
it took about a month and a half for all the snow to melt. i'm on the east coast too, everything in the west closes for the same reason even though they have a shit ton of snow.
there used to be a dry slope in niagra falls NY but it closed down cause NOBODY WENT TO IT