After Central Asians were walloped by winter last week, many may find it hard to worry about too little snow. But that is a problem facing the region’s farmers and dam builders of the near future. Snow is an essential ingredient in the delicate annual cycle shaping seasonal river flows and thus food and electricity production. While warming winters and shrinking glaciers have been obvious, and easy to measure, in Central Asia for decades, new data paint a fuller picture of what the future holds for these frozen reservoirs in the mountains.…