The United States has an Inauguration every fourth January 20th. Never has there been this much anguish over the expected weather. I have been to three inaugurations. One in sunshine with a foot of snow on the ground, one in rain, and one in freezing rain.
A much worse modern problem that will cause anguish and anger for unprepared people is all of the security checkpoints, fences, blockades, etc that prevent normal movement around the Capitol area.
That will cause much frustration!
On the other hand, I believe that crowd expectation has been wildly overestimated.
Not to mention the extra time spent standing outside waiting in line. If this ends up like the Promise Keepers event from the late 90's or that smaller event that happened a few months earlier, many people will die from exposure.