A NOAA projection shows where the spill is expected to have spread by Friday, 18 June 2010. NOAA

Oil has begun invading beaches in Northwest Florida and is seeping into Pensacola Bay, leading state officials to warn that the Intracoastal Waterway may have to be closed to commercial traffic. Small deposits are already drifting to inland waters, and large concentrations are right off-shore and moving closer with every incoming tide. Closing the Intracoastal Waterway, a vital inland conduit for shipping and barge traffic, becomes more likely with each incoming tide, Sarah Manning, a state Fish and Wildlife officer, tells NBC station WJHG of Panama City. “You can see the sheen real well right here,” Manning says. “There’s a lot of weathered, small tar balls right here” in the bay.The spread of the oil prompted the National Oceanic and Atmospheric Administration to expand off-limits fishing areas north to Panama City Beach this afternoon. That brings the total area closed to fishing to 80,806 square miles, slightly more than a third of federal waters in the Gulf of Mexico. NOAA is offering an interactive mapping service providing a wide range of customizable information on the spread of the oil spill. You can track its progress and projected course here.

Spill threatens NW Florida; Intracoastal Waterway may close