Canadian Press: Geologist quoted on why airplanes can't take off or land through an ash plume

An article distributed by the Canadian Press about concern that the volcanic eruption in Iceland could have an impact on Eastern Canada quotes Marcus Bursik, professor of geology and an expert in tracking ash plumes and their effects on air transportation. The problem with the Iceland eruption, he says, is that ash is right over landing sites, so airplanes can't take off or get in. The article appeared in the Globe and Mail and Toronto Star, among other outlets.