The high-tech expedition that began this month to create a detailed map of the wreckage of the Titanic has been halted because of the approach of Hurricane Danielle. Though the storm never made landfall, it reached Category Four strength Friday. “It’s official. Hurricane Danielle will force us to temporarily halt operations at the wreck site as of early Sunday morning,” American group RMS Titanic, which holds exploration rights for the wreck, wrote on its Facebook page late Saturday. “The team is working through the night to complete as many mission objectives as possible. To ensure the safety of all on board, we are heading back to St. John’s, Newfoundland for a few days,” expedition leaders said.