This week’s cold snap has sent many Louisville-area homeless looking for warmth. But many shelters are already full.When the weather gets extremely hot or cold, some local shelters participate in “Operation White Flag,” in which they relax their rules to accommodate those seeking refuge.Coalition for the Homeless Director of Community Coordination Mary Frances Schafer says space is tight at some shelters, which are crowded with people who have lost their homes in the economic downturn.“If this were not a weather emergency, we’d probably be turning people away," says Schafer. "But because of the weather we don’t want anyone to die or to suffer extreme hardship because of the weather.”Schafer says Operation White Flag does not guarantee a bed, but insures a place to get out of the cold.