Just visited the Steckel boat ramp, the river is largely open from there going north, not at all south of Steckel.
That's 24-25 miles of river ice that still needs to melt before they will push out the ramps in Bismarck. I am guessing it will be sometime around the middle of next week before Merriwether boat ramp is usable. The river should start losing 2-4 river miles of ice per day over the coming week.
Note, the Steckel ramp is still not usable. There's a 20 ft, or more ribbon of ice on the east shore, including the ramp.