I could totally see that happening to me--anything that is out of the normal routine (and preparing for an icy, dark, slushy commute would count) could make me forget something so basic that I don't normally even think about it.

Good for you for commuting in this mess, though! My route is far too dangerous still (most of the roads I commute on have only one and a half lanes plowed for two way traffic, and still has packed snow and ice over a lot of that) so I wouldn't even dream of trying it! In the city it seems to make sense, though--biking would be faster than the snarled up traffic I've been hearing about.