Jesus in Matthew chapter 24 speaks of signs to watch out for indicating the end of the world, which should be of interest to preppers.
1- it'll last for at least "days",
2- Christians ("the elect") will have to go through it along with everybody else, so there'll be no easy way out for anybody.
3- God is going to cut it short, otherwise it'll be so bad that nobody would survive.
4- The sun and moon will be darkened, stars fall from the sky (ash and dust clouds after a nuclear disaster, or runaway volcanoes or meteor storms?)
5- Nobody can predict the date of when it'll be, not even Jesus.
Matt ch 24 (abridged)-
"You will hear of wars and rumors of wars, but see to it that you are not alarmed. Such things must happen, but the end is still to come.
Nation will rise against nation, and kingdom against kingdom. There will be famines and earthquakes in various places. All these are the beginning of birth pains.
Pray that your flight will not take place in winter or on the Sabbath. For then there will be great distress, unequaled from the beginning of the world until now-and never to be equaled again.
If those days had not been cut short, no one would survive, but for the sake of the elect those days will be shortened.
Immediately after the distress of those days the sun will be darkened,and the moon will not give its light;the stars will fall from the sky,and the heavenly bodies will be shaken. But about that day or hour no one knows, not even the angels in heaven, nor the Son, but only the Father.
Therefore keep watch..you also must be ready, because the Son of Man will come at an hour when you do not expect him."