This essay intervenes in current ecocritical debates about the relationship between fiction and environmental risk by analyzing the limits of risk theory in the deep time of the Anthropocene. Although contemporary ecocriticism argues that we must move from apocalyptic depictions of risk to realistic ones, this essay examines fictions of nuclear waste commissioned by the Department of Energy to show that a risk-based realism is used to maintain the status quo of settler colonialism. It then turns to a countermodeling of the futures of nuclear waste by Leslie Marmon Silko in Almanac of the Dead (1991), where uranium's longue durée future, impossible to imagine from a human perspective, recasts the present as a space in which the unlikely, implausible, and unrealistic saturate the everyday. For Silko, the apocalyptic futurelessness that nuclear waste seeds into our present is a vital formal resource for unsettling colonial realism in the contemporary United States.