Historically low temperatures caused large swaths of the Chesapeake and Delaware bays to ice over.
On Nov. 29, there was zero ice on either of the bays or the Potomac River. But after weeks of cold Arctic temperatures, from the polar vortex, ice has covered large areas of both the Chesapeake and Delaware bays.
The Jan. 7 image allows you to see the ice especially abundant in the coves and backwaters on the Eastern Shore. Prevailing winds from west to east push the ice from one side of the bay to the other.