Australia has begun evacuating thousands of people from its northeastern coast ahead of a cyclone that could rival Hurricane Katrina in its destructive power. Cyclone Yasi has been upgraded to a Category 4 storm. Forecasters say it is likely to further strengthen and could generate winds of up to 175 mph before it hits land on Wednesday morning. An official warning has been issued saying it poses a "serious threat" to communities in north Queensland. More than 400,000 people live in Yasi's predicted path, which includes the towns of Cairns, Townsville and Mackay. The region, which takes in Australia's Great...