Today the Palm Beach Post reprinted the WSJ article. I dont know if the original had this response from NW but as it is short, I will post it here.

Northwest, which faces at least three lawsuitws from passangers stranded on various flights, says it made mistakes that weekend.
But it puts most of the blame on a "once-in-a-generation storm." The carrier says it erred in contiuning to send flights into and ouf of Detriot despite the blizzard. It concedes that its plans for handling "irregular" operations in Detroit were inadequate and that communications broke down between its operations center in St. Paul, Minn., and Detroit.
It also cites the fact that fewer than half its usual ground operations employees showed up for work because of the weather, paralyzing the movement of planes into and away from gates. Equipment failed in the extreme conditions; some of it, the carrier acknowledges, had not been winterized.

TW