A hybrid organization scheme combines multiple schemes to serve different needs within the same information space, often using one scheme at a higher level of the hierarchy and a different scheme at a lower level, or offering two alternative paths to the same content. The U.S. House of Representatives' directory of representatives illustrates this well: it's organized primarily "By State and District", a geographical and numerical scheme, with an alternative "By Last Name" path that's fundamentally alphabetical.
Hybrid schemes can genuinely serve people better when done carefully, but the source material is blunt about the risk: combine schemes carelessly and you create what it calls an "unusable Frankenstein-monster mashup." As a general rule, using a single scheme across an information space's primary content makes that content easier for people to understand as a coherent whole.
A hybrid scheme should feel like two clear doors into the same room, not a maze where nobody agrees on the layout.
The audience-then-topic combination is fine, but the duplicated emergency content across sections uses inconsistent terminology and content, creating confusion. Layering audience at the top level and topic within "For Residents" is a common, reasonable hybrid pattern, it isn't itself the source of the breakdown here. The actual failure is that the same underlying information was duplicated with inconsistent terminology and content rather than genuinely shared between the two access paths.
This is the important contrast with the House of Representatives example. "By State and District" and "By Last Name" are two different organizational views onto the exact same underlying directory records, not two separately maintained copies that can drift apart. The government site's emergency content, by contrast, was duplicated and then edited independently in each location, which is exactly how the two versions ended up inconsistent and confusing residents about which one was current.The fix follows directly from that contrast: maintain the emergency content once, as a single source, and surface it through both the "For Residents" and "For Visitors" paths via linking or a shared content component, the same way the House of Representatives directory presents one set of records through two organizational doors, rather than keeping two versions that can silently fall out of sync.