I think it will be the smoke of Ashkelon burning. They are shelling it now, and it is where the chlorine gas is made to sterilize the entire nations water supply. They crack that pressure tank and everything downwind that breathes oxygen is dead.
That may be why the scriptures mention Ashkelon destroyed, but ecron and Ashdod are uprooted in mid day. Evacuation?
In Gaza which is due south of Ashkelon, there will be no evacuation, the Egyptians will keep the border sealed, till the gas and smoke hits them. By then it will be too late.
Perhaps you could post your speculations regarding specific verses and such a war???