The so-called Polar Vortex which brought sub-freezing weather to 90 percent of the United States, brushed up against Rockdale Monday and Tuesday with minimal effects. Low water pressure in part of Rockdale early Monday was traced to ice forming inside the city water system at the Mill Street water plant. City employees, including Shane Whitmire, above, worked to thaw out the pipes and restore pressure. Lows of 20 and 18 were recorded Monday and Tuesday mornings. A warmup is expected to boost highs to 70 by Friday.