<p>The 1983 flood along the Colorado River corridor pushed the Glen Canyon Dam to its breaking point and embodies Charles Perrow’s conception of a normal accident while also revealing limitations in his treatment of ecological dynamics. Fueled by a powerful El Niño arising in the Pacific Ocean, an abrupt and late season snow melt in the Rockies, and errors in forecasting basin-wide runoff, Lake Powell surged eight feet above full pool and just seven feet from the crest of the dam standing 710-feet high. This necessitated emergency releases through the spillway tunnels which triggered cavitation of the concrete lining and the underlying sandstone abutting the dam. Extending Perrow’s theory of normal accidents by integrating Andrew Pickering’s neo-materialist thought, I introduce the concept of “hydro-materiality” to foreground the distinctive and variable properties of water interacting with hydraulic infrastructure. Hydro-materiality illustrates the active, efficacious characteristics of water, the trans-scalar dynamics ranging from the Pacific to localized hydrology, and the liabilities of a dualist managerial framework envisioning the dam as a closed or bounded system insulated from, while also containing, the vagaries of nature. Flooding at the Glen Canyon Dam illustrates that catastrophic risk can arise due to the complexity and tight coupling derived of large-scale infrastructure and hydro-materiality in its various phase transformations and emergent, unpredictable characteristics. It is a catastrophic potential that is exacerbated when organizational actors are committed to a dualist, probabilistic, and technocratic frame of reference failing to recognize the materiality and performativity of water.</p>