Crisis intensification and acceleration (e.g. the triple disaster in Fukushima, the COVID-19 pandemic, and the increase in extreme climatic events) have raised new challenges. Recent research went a step further by exploring new types of risks: compound risks. This article examines different definitions of compound risks and identifies their differences and common features. Starting from a definition restricted to the combination of natural hazards, the concept progressively unfolds to include a combination of hazards and local vulnerabilities, including the competition of different resources for mitigating their effects or the effects at different scales. Our article contributes to this theoretical effort. We explore how compound risks are envisioned in the current practices of preparation by actors in charge of risks management and crisis preparation, through 3 cases studies: medium size towns in France, Le Havre and Nantes, facing urban risks; a case study of the COVID-19 pandemic management at the French governmental level; and the doctrines in the case of a nuclear accident. Compound risks are understood in relation to scaling. The change of nature brought by a change of scale is explored through interdependencies, threshold, and rupture effects, which are intertwined with collapse. Are risks and risk management scalable? Compound risks consequences for political response are also studied. They may call for new types of governance, new modes of preparedness, and even new institutions. We conclude that compound risks question the very paradigm of risk management and crisis preparedness and may call for entirely new ways of facing extreme situations that question the very role and agency of politics.