Fontana dam release causes icy rainbow

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GRAHAM/SWAIN COUNTIES, N.C. — After days of heavy rain last week, river managers sought to create more room in Fontana Lake to prevent further flooding, according to WBIR.

“Sometimes we can’t get enough water out fast enough through turbines, so we run the turbines first to generate hydroelectricity, and we augment it with either sluicing or spilling,”  Tennessee Valley Authority General Manger of River Scheduling Chuck Bach told the Knoxville News Sentinel.

For the first time in 13 years, the Tennessee Valley Authority began using a sluice tube behind the dam to lower water levels. That works out to about 128,000 gallons of water released per second.

A ramp at the bottom of the sluice tube was created to diverted the water, which created an enormous amount of spray that turned into snow and freezing droplets in the cold air. The water encased the nearby trees and grass in ice.

In the sunlight, the blowing mist also created a vivid rainbow effect.

Source: WBIR and NBC News