(Reuters) - An unusually warm winter is dampening prospects for the eastern American ice wine industry, with fewer frozen grapes being harvested and less of the dessert wine being made, raising prospects for higher prices for consumers. During a long-overdue cold snap in an otherwise balmy winter, growers raced to pick tons of frozen grapes in a single night on January 3, about a month later than the usual harvest. "It was one of the latest ice wine pickings we've had," said Donniella Winchell of the Ohio Wine Producers Association.