For vendors, again, make sure you have all necessary contact information, and develop backup plans in case vendors are unable to get necessary products to you. (A disaster in their area that's nowhere in the area can still have significant impacts.)
When it comes to customers, keep the contact information of your most critical ones, so you can stay in touch with them during any period you're shut down. And try to have a plan in place to keep them supplied until you're back up and running.
Update all contact lists regularly and make sure they're accessible from any location. The important thing to keep in mind is it's critical to respond promptly, accurately and confidently to all of these groups. That can be tricky when you're dealing with the stress of an emergency, so Homeland Security noted it's best to have pre-scripted messages for each group — meaning you'll have to consider a number of different disaster scenarios and have the right messaging for each one.
3. Develop a continuity plan.
The heart of a disaster plan is a continuity plan, since it helps businesses continue operating even after an emergency. First, identify which operations are essential (or time-critical), and designate which employees will carry those out. This may require some cross-training of employees in advance (which can also come in handy if you an essential staffer leaves for another job).
The government suggests continuity plans be built using four steps: Conduct a business impact analysis to determine the most critical business functions. Next, develop recovery strategies to fill potential gaps brought on by an emergency. Work with a team, if possible, to develop the formal plan, as employees might think of weak spots the owner might miss.
Finally, educate your entire staff about the plan and train them on their responsibilities.
4. Do a threat analysis.
Business owners will want to factor in all potential hazards when creating their emergency plan. Some disasters, like fire and tornadoes, can happen anywhere. But it's wise to conduct a risk assessment of your businesses location to see what else could happen.
Are you within striking range of a major hurricane? Has there been any historic flooding? If you're in any sort of metropolitan area, have you considered terrorism? And don't forget cyber attacks. (Too many small business owners actually downplay that threat: Only 2 percent of the small-business owners surveyed in the CNBC/SurveyMonkey Small Business Survey said they view the threat of a cyberattack as the most critical issue they face.)
5. Run drills.
A good plan is useless if no one knows how to execute it when disaster hits. Work with employees regularly to ensure things will run smooth in the case of an emergency, and have a loyal customer and vendor you can use as test subjects during those drills. I
It may seem a waste of time, but if the unthinkable happens, it could mean the difference between a company's survival and an out-of-business sign.
—By Chris Morris, special to CNBC.com