The Iowa River between the Highway 330 bridge and the downstream old railroad bridge remained in locked but weakened ice earlier this week. Air temps in the low 50s was gaining strength to melt ice from above. Warmer waters flowing under the ice are silently adding to the breakup. Once a critical point of weak ice is reached, this entire segment of the river will become a continuous series of ice rafts bumping and grinding against each other as they make their way downstream.