The tweets you should follow in a crisis aren't necessarily the most obvious

Some interesting research based on the Arab Spring uprisings suggests that the best people to follow on Twitter during a crisis are often not particularly influential on Twitter outside the crisis. Likewise, they aren't likely to have had many followers before the event. Essentially, it's evidence supporting the common sense idea that, if you want the most accurate and relevant information, your best bet is to find people closest to the source, rather than relying on third-hand accounts.