April is noted for showers and also represents the foggiest month for South Louisiana. On this date in 1952 the tankers Esso Suez and Esso Greensboro collided in dense fog, 200 miles south of Morgan City. The Suez incurred a 20-foot bow gash with both ships bursting into flames. River pilots are trained to navigate during episodes of dense fog not only on the rivers but within simulators that replicate a variety of rough weather scenarios. Included within the scenarios are river levels and snow melt that increases those levels. Fog was the reason for a horrible disaster recognized as the worst aviation accident in history.  Two Boeing 747s collided on the runway in the Canary Islands in 1977, killing 582. On July 25, 1956, the Andrea Doria sank after colliding with the Stockholm in dense fog, 45 miles south of Nantucket Light taking 51 lives.