I thought this was cheery:

"All evacuation plans may not be realistic. For example, the escape plan for the Maine Yankee nuclear power plant in the United States was unfeasible. The large summer tourist community on the end of a 12-mile-long peninsula "in downwind Boothbay Harbor would face a terrifying drive up one winding little road toward the plant, where they would have to turn onto the pandemonium of U.S. 1 right next to ground zero..." A local attorney and former state senator Stanley Tupper stated that "Nothing short of a wide-scale evacuation by sea could have saved all these people."

http://www.ecologia.org/npp/evac.html

I think the difference between evacuating and hunkering down is usually divided between HAVING to evacuate. That's all that would get me out of here. If the water is too high, if the fire is too big, if the chemical spill is toxic.

For the rest of it, I have more useful stuff here than I could pack into the car.

It's a last-chice scenario that I believe Dweste had in mind, not IF but WHEN.

Sue

I'm reminded, I was driving around Northern Spain with a friend and remarked on how few of the hillsides and hilltops had houses on them - in the US this was prime real estate, people with money paid for the view. In this area the best houses were in valley bottoms, near the sea, etc etc. Nice, but seemingly not as nice as being on the hilltop. Inigo said the hillsides were never developed, the land was held out of public ownership for the most part, and that people preferred to live where there was a water system to fight fires. Now, a big factor was Franco - a dictator for 40 years who discouraged most public largesse and who had a society that also discouraged big thinking. But the hills are hit by tremendous wildfires every 50 or 100 years or so, and if not wildfires then winter ice keeps people down low, and then there are infrequent earthquakes. They live in a culture with a longer view, across generations, a social memory of previous devastation that tells them Its Not Worth The Hassle of building up the valley sides. Whereas in the US we've built water supply up hillsides pushing water to places where it generally can't go, they decided generations ago not to do that.

It sounds silly, but I did consider a volcanic lahar when siting my current house, worst case the muck will just lap at the base of the glacial moraine to the south, we have extensive lake shorelines to help protect us. But I wasn't aware of the recently found and chaqrted Seattle Fault, which gives the entire region a 9.0 scale jolt every several hundred years, and our house lies about 150 yards north of it. I am always indifferent to trees, which do the most to prevent flight in windstorms and flooding. Just as I'm sure 350,000 people down in the Green River Valley were indifferent to the potential for flooding when they moved into their homes there, because there hadn't been floods for 40 years since they had develped the Howard Hansen Dam. Now that dam leaks, and those people may be in aworld of hurt this winter. You never know what may transpire to do you in...

The "when" to flee and how to figure that out is the key question of the thread.

Seattle has EIGHT earthquake faults under it, not one. I think of that nearly every time I drive there (four or five times a week or more) and look at all the tall buildings.

http://earthquake.usgs.gov/regional/pacnw/activefaults/sfz/sfzmapping.php#fault1

Sue

Danger: Flood. Sailboat could be swept away and sunk. Edit: Utilities could be disrupted or supplies unavailable beyond bug-in capability.

Data to monitor:

1.Tide height and direction from tide tables.
2.Expected spring runoff river crests from media and internet.
3.Levee failure location announcements on media and internet.
4.Location of levee failures on Delta map.
5.Observed sudden change in water height or flow direction contrary to tide tables.

Known limitations:

1.Boat sails or motors no faster than 10 mph in the best of conditions.
2.Road out crosses two islands below sea level and one bridge between islands.
3.Freeway is about 4 miles away and is elevated.
4.Levee road at marina is elevated.
5.Government flood defense calls for blocking freeway underpass to contain [and incidentally heighten] flood water from close levee failure, which would block the road across the last island between the boat and the elevated freeway.

Bug-in preparations of note during Spring:

1.Extra mooring ropes and boat bumpers between boat and marina dock.
2.Extra fresh supplies in boat.

Bug-out?

1.By car if levee failure is close, but not located to cut off evacuation road.
2.By car if levee failure threatens to sweep away marina dock.
3.By car if levee failure results in boat becoming uninhabitable somehow.
4.By boat if flood waters block access to freeway for time extended beyond supplies.
5.By boat if flood destroys nearby supply sources or renders them unreachable by car for a period of time that threatens re-supply.

Sometimes events won't let you just plan...

It was a routine morning about twenty years ago at Anacapa Island (Channel Islands Nat'l Park). Staff and about thirty visitors were leaving the boats for a day on the island. Suddenly, five blasts from the boat's horn and the announcement. "We have just been advised by Hq to evacuate Anancapa Island immediately. Everyone, no exceptions, return to the vessel."

A missile had exploded on the launch pad at Vandenberg AFB (Point Conception) releasing a noxious cloud of who-knows-what downwind onto the northern Channel Islands. Everyone got back on the boat and the skipper called Hq, asking,(only half in jest) "Well, we've retrieved everyone from Anacapa. Now, should we stand out to sea, or return to the mainland to die with everyone else?"

As it turned out we returned to the mainland OK but three park employees on San Miguel Island were not so fortunate. The cloud did reach SMI, and they returned to the small ranger station, shut the doors and windows, and await an aircraft which removed them from the island. There were some after effects from exposure to the toxic cloud.

I would paraphrase Gaston Rebuffat, a famous French alpinist, "You will always regret fleeing too late, you will never regret fleeing too early."

As recent events have shown in SoCal, wildfires are a big problem. I have never actually left, but we have been packed up and ready to leave twice in the past fifteen years. I acted well in advance of any "official" instructions. A written, posted list is a big help.

Like others, when the big earthquake comes, I plan to shelter in place, but you must be flexible and ready to think on your feet.

[Why would this preclude doing some thnking now, before the fog of stress and questionable information floods your harried decision-making during a disaster / emergency?]

Danger: Earthquake. Utilities could be disrupted or supplies unavailable beyond bug-in capability. Could cause levee failure and flood – see flood plan. Could cause fire – see fire plan.

Data to monitor:

1.Epicenter and road damage reports in media and on Internet, if available.
2.Road and water travel restrictions.
3.Bug-in supplies.
4.Re-supply disruption reports, ditto above.
5.Communication disruptions.
6.Evacuation center locations.

Known limitations:

1.Boat sails or motors no faster than 10 mph in the best of conditions.
2.Road out crosses two islands below sea level and one bridge between islands.
3.Freeway is about 4 miles away and is elevated.
4.Levee road at marina is elevated.
5.Government flood defense calls for blocking freeway underpass to contain [and incidentally heighten] flood water from close levee failure, which would block the road across the last island between the boat and the elevated freeway.

Bug-in / other preparations of note after earthquake:

1.Extra mooring ropes and boat bumpers between boat and marina dock.
2.Extra fresh supplies in boat and car.
3.Gas fill-up of car.
4.Fill boat diesel tank and spare container.

Bug-out?

1.By car if levee failure is close, but not located to cut off evacuation road.
2.By car if levee failure threatens to sweep away marina dock.
3.By car if levee failure results in boat becoming uninhabitable somehow.
4.By boat if earthquake or flood waters block access to freeway for time extended beyond supplies.
5.By boat if earthquake or flood destroys nearby supply sources or renders them unreachable by car for a period of time that threatens re-supply.

BTW, for iPhone users who want an real time, worldwide, USGS earthquake report there's an app called QuakeWatch. Very cool, and informative. You can select data by location, intensity, etc.