Population growth and crowded coastlines have experts bracing for more destructive tsunamis similar to the one that struck Japan last year. For example, experts expect the Pacific Northwest to be hit by a tsunami at some point, but the effects could vary based on the season. "[I]n the summer there can be 100,000 people on the coast. We could have tens of thousands of deaths," said geographer Nathan Wood of the U.S. Geological Survey. Kerry Sieh, who works at the Nanyang Technological University in Singapore, said: "The fundamental problem is that there are seven billion of us, and too many of us are living in places that are dangerous."