The damage that hit a Marshall County boat marina over the weekend was caused by 90 mph winds, experts said Tuesday morning.
The National Weather Service said the storm that damaged Little Mountain Marina Saturday afternoon caused a gustnado with high winds.
The storm uprooted a tree at the lake shore, broke windows and tore roofing at the marina itself, and snapped small trees.
Two pine trees also snapped near Murphy Hill Road, according to the weather service.
The weather service said witnesses reported seeing a "waterspout without water" form over Lake Guntersville and move toward the shore, causing the damage.
Gustnadoes occur along gust fronts and are not connected to actual rotation in thunderstorms.