Hungry Horse Dam is 564-feet-high and has a variable-thickness concrete arch structure with a crest length of 2,115 ft. The dam and appurtenant works contain 3,086,200 cubic yards of concrete. The spillway is the highest morning-glory structure in the world. Water cascading over the spillway rim drops a maximum distance of 490 feet. The capacity of the spillway is 50,000 cubic feet per second, and the reservoir has a total capacity of 3,468,000 acre-feet.
Foundation: Siyeh limestone in regular beds ranging from a few inches to several feet thick, made highly insoluble by impurities. Cut by one major and several minor shear zones, and one major bedding-plane slip.