Catchy, eh? To review basic physics and orbital mechanics (neither of which I ever took), the Coriolis effect is when it appears an object (a plane or a cannonball, for example) is veering off course, when actually the earth is rotating under the object - essentially, and with apologies to my buddies who are artillery types, the target is moving so you have to plan for the Coriolis effect in order to hit the target.
Applying the Coriolis effect to your estate planning (which, for our purposes today, includes advance directives like medical and financial powers of attorney), say you've named your spouse as your primary agent (executor, trustee, POA holder, etc.) and your spouse dies before you do. If you haven't planned for that contingency (you were wondering when I was going to get to that!), then your document can't help you because there's nobody to exercise the powers you granted. That's why we always insist that our EP clients provide at least one alternate agent for each position. The other thing you can do is make sure you're reviewing your documents every 3-4 years so that if it's necessary to add or remove a person or a bequest, you can make those revisions before it's too late. This turns your cannonball of a document into a GBU (guided bomb unit) that you can adjust while it's on its way to the target!
Can you tell I've been reading military stuff lately? As always, the above is legal information, not legal advice, and it's based on Texas law because I'm a Texas lawyer. Your situation will be unique to you, so you should always consult an experienced estate planning lawyer before making these decisions. And remember: with wills, powers of attorney and directives to physicians, when you need it, it's too late to get it. So don't wait.