Does the Missouri River generally freeze over in the winter? Bruce, in January 1865 the Missouri River was completely frozen over, at least along a part of it, apparently giving Confederate irregulars free access back and forth across it, which, in turn, may have accounted for increased partisan activity along it. Of course if the river regularly freezes, this may not have been responsible for an increase in activity over the same time frames from previous years. Some of you who live along the Missouri may be able to provide additional insights. If nothing else, the below entry provides information on the weather conditions in west central Missouri during the specific time frame you requested. See--

"Compendium of History and Biography of Linn County, Missouri," 1912, page 75

"...In the winter of 1864-65 Jim Rider and his band of bushwhackers, to the number of about fifteen, had an encampment on an island in the Missouri river, near the Carrol county side, not far above and on the opposite shore from the town of Waverly, Lafayette county. The river was frozen over for a portion of the time, the weather being very cold, and Rider could reach either mainland when he wished. From his retreat, which was a snug and secure one, the daring bushwhacker made frequent forays into the country on both sides of the river, in search of plunder more than for the purpose of shedding blood, and uniformly returned successful and in safety to his covert well hidden in the thick willows of the Missouri river island.

"On the night of the ninth of January, 1865, Rider, at the head of about a dozen of his band, made a raid upon Linneus. It was about 10 o'clock when the bushwhackers reached the town. The moon was in the first quarter, and, save that it was occasionally obscured by flying clouds which scudded across its face at intervals, gave a fair light. There was a light fall of snow upon the ground and objects could be seen with tolerable distinctness...."