On 11 March 2011, the devastating earthquake at 9.0 on the Richter scale and the associated tsunami struck the east Japan, especially in Tohoku region. In spite of immediate dissemination of earthquake early warning and tsunami warning by the Japan Meteorological Agency (JMA) to the public, the unprecedented scale of the tsunami caused overwhelming damages. The number of confirmed dead and missing reached around twenty five thousand. Since the occurrence of this disaster, the JMA has been putting its best efforts to fulfill its responsibilities by issuing various information from earthquake and tsunami warnings to meteorological information tailored for the affected people in a timely manner. The presentation aims to introduce JMA's emergency responses and share lessons learnt under such a difficult situation, hoping their utilization for the further enhancement of the disaster management in the future.

The earthquake and tsunami increased vulnerabilities to meteorological disasters, such as sediment disasters, flood, and inundations, in the affected area, by shaking and loosening the soils and damaging the embankments and drainage facilities. Responding to such situations, on 16 March 2011, JMA changed the criteria of Heavy Rain Warnings to the affected areas based on site investigations and consultation with the local governments. The earthquake also largely sank the ground level of the Pacific coast, and increased the risk of the inundation and flood in the coastal regions, especially during spring tides. On 17 March 2011, JMA announced the need for people, especially in the affected coastal areas, to pay attention to the Storm Surge Advisory issued by JMA. In addition, after consultation with relevant local authorities, JMA is going to tentatively lower criteria for storm surge warnings and advisories in those areas from 26 July 2011.

This disaster also caused the significant reduction in the electricity supply capacities by damaging Fukushima Nuclear Plants. The Government of Japan has appealed for people to save on electricity, such as raising the temperature settings of the air conditioner. Since such electricity saving measures have possibilities to increase the risk of heat stroke, JMA started providing information on extreme high temperature named “Extreme High Temperature Forecast” on 13 July 2011.

Sendai Airport, in charge of aviation meteorological services to local airports in Tohoku region, was struck by the tsunami and lots its operational capability. According to the JMA's Business Continuity Plan, Haneda airport immediately started remote back-up operation for Sendai airport for issuance of TAFs to those airports. One thing to note is the heavily reliance on air transportations for the support activities for victims, such as search and rescue (SAR) and deliveries of injured people, because land and marine transportations were devastated by the quake and tsunami. Some of the neighboring airports were used for this purpose. With respect to the weather briefing at the airports, guidance not only on aviation weather but also on weather information around the affected area was requested for support of those activities. Release of radioactive matters from the Fukushima Nuclear Plants posed new problems to aviation services, namely how to issue SIGMET on radioactive cloud.