The Grant County Public Utility District lowered the classification Tuesday night.
The downgrade is the result of engineering surveys conducted Monday and Tuesday that show continued stabilization of the 65-foot long crack found last week on one of the dam's spillways.
As of 6 p.m. Tuesday, surveys show that the impacted area is stable.
The PUD says the fracture has closed and the damaged section of the spillway monolith has moved back upstream by nearly 1.75 inches. That's the result of the utility's actions to lower water above Wanapum Dam and reduce pressure on the damaged spillway.
The dam is located a few miles south of Vantage on the Columbia River.