Tens of thousands of migrant workers fleeing Libya found themselves in a desperate crush of refugees trying to cross the border into Tunisia last march. More than half of the estimated 180,000 people fleeing have sought refuge in Tunisia since the uprising against Libyan leader Moammar Gaddafi began Feb. 17, but the sharply increasing flows over the dusty desert crossing of Ras Jdir were forcing Tunisian authorities to periodically close the border to stem the tide. The effect of that has been to create a backlog of around 20,000 people waiting on the Libyan side.