Hammond residents woke up to a spectacular sight outside their windows Friday morning. Many Northshore residents sent WDSU photos of a massive shelf cloud. WDSU Meteorologist Devon Lucie explains how these clouds form:"A shelf cloud forms from an ‘outflow’ boundary, or what can be thought of as a ‘mini cold front,'" said Lucie. "Rain-cooled air from a storm spills to the ground and pushes out from underneath the cloud, lifting the surrounding air. As it rises, water vapor immediately condenses into the cloud directly above the leading edge of the cooler air giving it its unique and ominous shape."The cloud could be seen in Covington and Hammond Friday morning.