From a Linguistics standpoint, the 'F-word' here is an Expletive Attributive modifying the Strait—not a vulgarity. It’s a high-stakes intensifier for extreme urgency, much like calling an elite athlete a 'f***ing good player.' Focus on the crisis, not the adjective.
An expletive attributive is a "filler" adjective used for emphasis. It’s the linguistic equivalent of hitting a table with your fist to make a point—it adds volume, not "vulgarity."