Not to discount the salts, but at some point, the vaporization would tend to leave behind the salts.
So, given the prevailing winds, the damage might be greatest immediately downwind of an impact. That's to say a Pacific
strike off of CA would do a number on their agricultural lands.
And while salt isn't effective below a certain temperature for melting ice, there would be the potential for increased
flooding from mountain snow packs too.
Interesting. As far as this specific Gulf graphic, I find myself wondering about all that water, at least halfway up the Mississippi Valley, and the stress it would exert upon the New Madrid fault, too. As bad as the death and destruction from coastal inundation would be, it's slowly dawning upon me that it would just be the beginning.