So, I’ve gotten myself acquainted with the timeline on the wiki over the last year, and I came up with a theory after reading between the lines.
On the surface, it seems that what happens is that zero-hour coincided with unstable laboratory portals opening in New England, followed by more “natural” fissures in reality opening up elsewhere in the world, coinciding with fresh incursions by the Blob and creatures from unrelated planes of reality. Following this logic, the military abandoned New England for the purpose of dealing with the nasty gribblies appearing in the rest of the country.
That being said, the hypothetical speed at which the Blob could infect the entire world’s population if it were distributed from portals around the world would be, while extremely fast, still a longer process than five or so days, based in how low-intensity the pre-Cataclysm outbreak was. Because if this, I speculate that the additional portals around the world are actually red herrings, which only carried non-Blob entities, while the initial surge of the Cataclysm itself somehow encompassed the entire globe instead of just New England, dispersing the Blob in relatively small amounts everywhere at once.
Any thoughts on this? Forgive me if this was debunked or confirmed elsewhere. For all I know, the official timeline may be outdated considering its age.