Beth,
With the hood up and some warm layers underneath this coat would do a pretty awesome job at keeping you warm in some very chilly temps.

You might want to consider the Patagonia Tres. It has a similar (same?) down parka but it zips into a water/windproof hard shell. My wife wore this in similar temps in Minnesota and was very pleased.

http://www.backcountry.com/patagonia-tres-down-parka-womens