Oh my! Because the Common App is terrible, Columbia has extended the RD deadline, just like they had to for the ED deadline. The deadline is now 11:59 pm on January 6 (literally the last minute of the Christmas season).
In addition to extending the deadline, a post on the Admissions site says, harried applicants can opt to use the Columbia application (not seen since the Class of 2014 applied, which was before Columbia switched to the Common App for a sweet, sweet increase in
BUT, Admissions notes: applying twice will not give you twice the chance. Only apply once, with one of the applications. And, italics theirs, “we ask you not to call or e-mail with application tracking requests until after February 10, 2014.”