New Des Moines Register poll released tonight-
Carson plummets to 13% (from a high of 28% in October)
Rubio at 10%
DES MOINES — Senator Ted Cruz of Texas surged to a 10-point lead in a new poll released Saturday of likely Republican caucusgoers in Iowa, a sign his campaign is gathering momentum and suggesting a long nominating fight is ahead.
Donald J. Trump, who continues to lead most national polls, was second in the Iowa poll, with 21 percent naming him as their first choice, compared with Mr. Cruz’s 31 percent.
Ben Carson, after leading an October survey by the same pollster, commissioned by The Des Moines Register and Bloomberg Politics, tumbled to 13 percent, followed by Senator Marco Rubio of Florida at 10 percent.
The survey, by one of Iowa’s most respected pollsters, comes as Mr. Trump is increasingly hoping that a win in Iowa, whose caucuses are less than eight weeks away, will be a lightning strike on his way to the nomination
More here at the desmoinesregister who is calling this a 'Big Shakeup'