White Powder

I'm sitting in my apartment off Lake Michigan in Chicago, looking out my window at ... nothing.  It's just a cloud of white.  The snow is coming down so hard that I can't see the building across the street.  In fact, I can't see the street.

I looked at the Weather Channel app on my iPhone this morning and there was a lakefront flood warning.  This is a little creepy under the best of circumstances (Lake Shore Drive is one of the major traffic arteries in the city); it's really freaky when the lake is frozen over for the first hundred yards or so.  There is this loud craching noise I hear every few minutes or so.  At first I thought it was snow plows, but I heard it too much for that.  My latest theory is that it's the wind hittting the ventilation system shafts or something similar.  At least I hope that's what it is, because the only other explanation that comes to mind is that it's pieces of buildings flying off in the wind.