Video of the El Cajon Blue Hole in the Thunder Bay National Marine Sanctuary near Alpena, MI. The El Cajon boils show groundwater entering from the bottom of the sinkhole, creating a boiling effect as water flows through sand. Video provided by the Great Lakes Environmental Research Laboratory - http://www.glerl.noaa.gov
Very cool I've seen these on land in Atlanta very neat sight to see underwater or above ground
robertleftwing 5 months ago