System storage is 58.0 MAF; 1.9 MAF of the 16.3 MAF of flood control storage is occupied. More than 88% of the flood control storage is available to store runoff this spring and summer. The heavy plains snowpack in South Dakota is melting over frozen ground. Frost depths are deep in North Dakota (upper right graphic) and South Dakota (lower right graphic). For the entire upper basin frost depths click here. The 3-week forecast with our projected reservoir releases has been updated .