What would you do if all of a sudden a terrible emergency was announced and you needed to evacuate? We've seen how easy it is for 395, 182, and 82 to get backed up during high-traffic times. Here are some alternatives.

1) Pack a 72-hour kit for each vehicle. This is everything you'd need to survive 72 hours outside your home (change of clothes, basic toiletries, medications, water, snacks, etc.) Also, try to always refill your gas tank when it's half empty so you always have at least half a tank of gas in it.
2) If you're escaping radiation from Hanford or smoke from a wildfire, make sure you know which direction the wind is blowing and go the opposite way! Most weather pages will tell you wind direction and speed but you can go straight to the source by visiting the Pendleton weather station's website.

If you need to go north, your only option is 240, which is dangerous because if high traffic or a wreck clogs traffic there is no alternative. You're stuck. For heading north, a smarter move is taking Van Giesen (224) to Benton City, then Old Inland Empire Highway until you can take Hanford Road north until you can re-connect with 24, or find a stretch of 82 that's clear.
If you need to go south, Webber Canyon Road or Dallas Road will give you several options.

If you need to go south consider Owens Road or Finley Road.
If you need to go north and the bridges are blocked, your best bet might be south on 395 and then north on 12.
Ditto for going east.
To go west consider taking Badger, Clodfelter or Locust Grove to Sellards Rd.

To go north use Rd 68 to Taylor Flats Road or 4th Ave to Glade Rd. If you're on the other side of 395 the Pasco Kahlotus Road might be your best bet.
To go east use Pasco Kahlotus Road or Ice Harbor Drive.
If you need to go south or west taking 12 south to Oregon and then another route from there might be your best bet.