Etherington, from Lincolnshire, and Powell, from Essex, won silvers in the downhill, slalom and super combined, plus a bronze in the super-G in Sochi.
They were the first British women to win a Winter Paralympic medal on the snow.
“Caroline and I now wish to follow different paths which we feel will be more fulfilling for us in the long term, Caroline with her instructing in Switzerland, while I would like to complete my qualification as a teacher and increase my motivational speaking,” Etherington said.
“It was an honour to represent ParalympicsGB and to make history at the Sochi 2014 Winter Paralympics.”