A helicopter carrying a pilot and three state workers crashed in a large remote lake on Alaska’s North Slope on Thursday night, officials have announced. A rescue and recovery dive team has been deployed but no survivors have been located at this time. “The official word is they are missing, presumed fatal,” Clint Johnson, the chief of National Transportation Safety Board’s Alaska region, said on Friday. The helicopter was carrying three employees from the Division of Geological and Geophysical Survey who had been conducting field work. It had been chartered by the Alaska Department of Natural Resources, the department said in a statement on Friday. “DNR is praying for our employees and the pilot, their families, and the DNR team,” the statement said. “We are continuing to await updates from the search and rescue effort.”