I wrote this post last year for the Harvard Business Review. Today’s sad news from Japan is a reminder of why we all need an emergency plan — for our families, our offices and our online communications.

Yesterday morning I gave a talk on social media to a group of Canadian government employees. The talk was organized by my sister-in-law, Jennifer Jager, who is part of the marketing team at Public Safety Canada that is responsible for promoting emergency preparedness across the country. The fifty civil servants in the room represented a good portion of the Canadian government’s social media diehards, but Jen was one of a small handful who’d been authorized to tweet on behalf of their respective departments.

After my talk, Jen and I went back to her office, where she showed me some of her team’s efforts to harness social media for emergency preparedness. Their key message: every family should be ready to survive an emergency for at least 72 hours. The star of the show is a great video by Common Craft, the creators of RSS In Plain English, on Making a Family Emergency Plan. Jen and I got into a conversation about the relative preparedness of our own households, and I struggled to understand why she’d need to have emergency kits in multiple locations.

“What’s really going to happen in Ottawa that could prevent you from getting home?”

“We could have an earthquake.”

Living in earthquake-prone Vancouver, I couldn’t suppress a skeptical “C’mon, really.”

Right then, the floor started shaking. We were feeling an earthquake. You can’t make this kind of thing up.

Five minutes later we had made it down the ten flights of stairs and into the parking lot, where civil servants were pouring out of the building. If you want to see an orderly evacuation, I highly recommend spending your next emergency in an office dedicated to emergency preparedness.

As soon as we were clear of the building, we pulled out our phones. My Twitter pals were reporting quakes in Toronto and Montreal, an area that includes about half the population of Canada. Reports of feeling the quake came in from as far as Boston. Jen’s Blackberry had an e-mail from her boss, asking her to update Twitter with Public Safety’s information on emergency preparedness.

Makes sense: when nature gives half your target audience a major reminder of why emergency preparedness matters, you want them to know you’re ready to help.

Easier said than done. When an emergency happens, even if it’s just a scare, everyone reaches for their cell phones. With 3G overloaded, Jen’s iPhone couldn’t connect to the Internet, so she couldn’t get the link to her department’s page of earthquake information. But even with the local network maxed out, long distance still worked, so we called my husband in Vancouver and walked him through the Get Prepared website until he found the right page. Jen then asked him to save a shortened version of the link in bit.ly, as http://bit.ly/72earth, easy for Jen to remember and enter on Twitter.

But before Jen could post the link, she hit her next snag: every Government of Canada tweet has to be posted in both English and French. Reaching a translator was out of the question, so we walked through the crowd of bureaucrats gathered in the building parking lot until we overheard a few words of French. We commandeered a francophone from the Department of Corrections, who translated Jen’s draft tweet into French.

Jen was now ready to log into Twitter as Get_Prepared, but 3G was still on the fritz. As a fallback, we walked the two blocks to a nearby Starbucks, where WiFi Internet access was running smoothly. She logged onto the department’s Twitter accounts Get_Prepared and Preparez_Vous and sent two tweets:

What you need to know about #earthquake risks, from Public Safety Canada http://bit.ly/72earth
Ce que vous devez savoir sur les risques d’un tremblement de terre, de la Sécurité publique Canada http://bit.ly/72terre

It took one hour for Jen’s tweet to go live online: not instant, but fast enough to land in the thick of a lively Twitter conversation about the earthquake, ensuring that lots of Canadians would find out about Public Safety’s emergency preparedness info. Mission accomplished? In this context, yes, but what if the earthquake had been a more severe an emergency with injuries and fatalities?

Jen’s experience was a dress rehearsal for her department’s use of Twitter in future emergencies. But emergencies aren’t limited to natural disasters: they can happen through product recalls, information leaks, industrial accidents (paging BP) and many other channels. Here’s how to ensure your social media team is ready for your next emergency:

Develop a separate social media policy for emergencies. On a day-to-day basis your organization may prefer a social media strategy that requires messages to pass through a couple of layers of approval or go out for translation. That can be challenging at the best of times, but during an emergency it can be the difference between getting your message out and missing a news cycle, or even a matter of life-and-death. Develop a social media policy that empowers a small number of people to quickly communicate via blog, tweet, Facebook or other channel in the event of an emergency, and agree on a clear definition of emergency so they know the circumstances in which it’s appropriate for them to communicate without prior approval.

Factor in internal communications. In an emergency, your own teams need be updated, if only as a way of helping get your message out. Let your team know the social media channels they can count on for the latest scoop on your company’s activities.

Incorporate hash tags. Jen included #earthquake in her tweet so it would get seen by people who were following the breaking news of the quake by tracking the #earthquake hashtag. Working #earthquake directly into the text of her tweet gave her room for a longer message.

Build up a message bank. Jen and her team were able to respond quickly after the quake because they had a bank of pre-approved content. Develop a set of messages you are ready to deploy via tweet, Facebook or YouTube (great for messages straight from leadership!) and keep them on standby.

Shorten your key URLs. Jen had to use a long distance workaround to get the bit.ly link she needed. You can avoid that challenge by identifying the 20 or 30 pages on your web site you point people to most often (like your press page, your CEO’s bio, or key instructional information) and creating easy-to-remember short links using bit.ly, tinyU.rl or a similar service. Then you won’t have to hunt for a URL before sending out your emergency e-mails, tweets or Facebook updates.

Plan for multiple trigger points. If your communications point person can’t get online, you need a plan B for deploying your message bank during an emergency. Ensure that your emergency communications team can access your message bank remotely, and have a few different options for getting online (for example, both smartphones and Starbucks user accounts).

Practice, practice, practice. Yesterday’s earthquake offered Public Safety Canada a natural opportunity to try out their emergency tweeting and to iron out the wrinkles. Your organization could find itself in an emergency at any time, perhaps hampered by Internet access issues, a management team that is out of communications range, or a web site that slows under duress. Any of these circumstances are a chance to rehearse your emergency social media plan, so the next time management goes on retreat, try posting an uncontroversial YouTube video, and figure out the way to navigate approvals when the C-level execs are all out-of-town.

As you put these plans in place, hold yourself to the same standard Public Safety Canada has set for Canadian families: the ability to last 72 hours in an emergency. If your social media communications can survive 72 hours of disruption to your Internet connectivity, senior management team or workplace access, you’ll know you’re ready for most eventualities.