The December tidal waves that hit Sri Lanka had one (sort of) positive aspect, the rushing water washed away thousands of landmines that had been laid by rebels and soldiers over the past few years. Unfortunately, many of these mines were not washed out to sea, they were just moved around on land. Now no one knows where many of these mines are. Clearing mines is usually made easier when the people who planted them kept records of where they put them, and shared that information with you. But not always. Weather is an important factor, especially in parts of the world where theres a lot of rain. Heavy rain storms will make the ground liquid, and let it move, taking landmines along. But this was a minor problem compared to what happened in Sri Lanka. Huge amounts of topsoil, and the mines they contained, were moved long distances by the waves. This can be seen by those mines that ended up on the surface in places where there had been no landmines before December 26th. Its the ones still covered by earth that cause the most problems. The army and LTTE rebels estimate that, together, they have planted about a million landmines. Several hundred thousand were in areas hit by the tidal waves. Efforts to count how many are missing are still under way. A few of the wayward mines have already gone off, and farmers along the coast have been warned that they will not be allowed to work their fields until mine detection teams have swept them. But this might take years. The mobile mines of Sri Lanka are going to be a problem for years to come.