end of May 2011, residents of Iwate, Miyagi, and Fukushima prefectures had requested the deregistration of 15,000 vehicles, meaning that the owners of those vehicles were writing them off as unrepairable or unsalvageable. Weather conditions Low temperature and snowfall were major concerns after the earthquake. Snow arrived minutes before or after the tsunami, depending on locations. In Ishinomaki, the city which suffered the most deaths, a temperature of 0 °C (32 °F) was measured, and it began to snow within a couple of hours of the earthquake. Major snow fell again on 16 March, and intermittently in the coming weeks. 18 March was the coldest of that month, recording -4 °C to 6 °C (25 °F to 43 °F) in Sendai. Photos of city ruins covered with snow were featured in various photo albums in international media, including NASA. Waste The tsunami produced huge amounts of debris: estimates of 5 million tonnes of waste were reported by the Japanese Ministry of the Environment. Some of this waste, mostly plastic and styrofoam washed up on the coasts of Canada and the United States in late 2011. Along the west coast of the United States, this increased the amount of litter by a factor of ten and may have transported alien species. Ports All of Japan's ports were briefly shut down after the earthquake, though the ones in Tokyo and southwards soon re-opened. Fifteen ports were located in the disaster zone. The north eastern ports of Hachinohe, Sendai, Ishinomaki and Onahama were destroyed, while the Port of Chiba (which serves the hydrocarbon industry) and Japan's ninth-largest container port at Kashima were also affected, though less severely. The ports at Hitachinaka, Hitachi, Soma, Shiogama, Kesennuma, Ofunato, Kamashi and Miyako were also damaged and closed to ships. All 15 ports reopened to limited ship traffic by 29 March 2011. A total of 319 fishing ports, about 10% of Japan's fishing ports, were damaged in the disaster. Most were restored to operating condition by 18 April 2012. The Port of Tokyo suffered slight damage; the effects of the quake included visible smoke rising from a building in the port with parts of the port areas being flooded, including soil liquefaction in Tokyo Disneyland's parking lot. Dams and water problems The Fujinuma irrigation dam in Sukagawa ruptured, causing flooding and the washing away of five homes. Eight people were missing and four bodies were discovered by