Final answer:
While the correct answer to what saved the people of south St. Louis in the specific scenario is not provided, lessons from Hurricane Katrina suggest that a combination of infrastructure, preparedness, and effective emergency response are critical in disaster situations.
Step-by-step explanation:
When looking at the situation of St. Louis, it seems that the answer to what saved the people of south St. Louis—whether it was improved warning systems, higher levees, luck and a shift in the weather, or evacuation—is not specifically detailed in the provided materials. Instead, we can infer from similar instances, such as during Hurricane Katrina, that effective disaster management can involve multiple factors, including evacuation plans, levee construction, and response from emergency services. However, in the case of Hurricane Katrina, the failure of the levees and the disorganization of emergency services, particularly affecting the African American community, indicate that infrastructure and a well-coordinated response are critical to saving lives during such natural disasters.