Critical lifelines depend on each other. Impacts to electricity cascade to affect communications and transportation; generating electricity requires water. It’s a complex system. For Los Angeles County’s Climate Vulnerability Assessment, we recruited more than a hundred experts from utilities, health services, and emergency management to help diagram their interdependencies - how do they rely on each other, how do they support each other? The resulting map helps us see how impacts to one lifeline can ripple out to affect others. By analyzing the network, we can start to prioritize investments not just by their immediate impacts but also by their systemic consequences.