This weekend will disappoint East Coasters hoping for a break from the recent spate of slightly-apocalyptic natural events. Earlier this week, the region was shaken and rattled; this weekend, it will be soaked and pounded by Hurricane Irene, a storm The Washington Post reports is “less than two days away from initiating a devastating blow to a large section of the East Coast.” When the storm makes landfall over the Carolinas, it is expected to bring along winds of over 100 mph—and in North Carolina’s Outer Banks, mandatory evacuations have already been ordered. But as we have seen before, there are always some people who don’t evacuate when hurricanes are approaching. Why?

According to a 1991 study in the International Journal of Mass Emergencies and Disasters, the biggest factors contributing to successful evacuation drives are perceived risk and the effectiveness of public officials. Surprisingly, a number of demographic factors, including “age, previous hurricane experience, previous unnecessary evacuation, general hurricane awareness, age, education, sex, and family status” were found to be “rarely, weakly, inconsistently, or never related to evacuation.” Rather, the study argues, the efforts of public officials matter most: The study notes that when people receive evacuation recommendations (or orders) from public officials, they are vastly more likely to flee an oncoming storm. During one storm, for instance, the evacuation rate of people who hadn’t heard the orders from public officials was only 20 percent; among those who had, it was 84 percent. And the wording of evacuation notices matters significantly. A weak recommendation invites a weak response, but vigorous dissemination of an order (which may include, as the study notes, a door-to-door effort by public officials) has resulted, in some cases, in evacuation rates of up to 97 percent. So let this post serve as one more warning: Check and see if officials in your area are telling you to get out of Irene’s path—and if they are, don’t ignore them.