The tropical cyclone season in the western Pacific typically kicks off in June. Cyclone activity is heightened particularly in the months of July, August and September. WeatherUnderground has a display of yearly maps of storms in the region. The map below for 2009 shows that several moderately strong cyclones (termed typhoons in this region) passed near the Fukushima plant area that year.
In 2010, cyclone activity was much diminished. Actually, this trend was noted globally. So we don’t know what 2011 will bring, although some forecasts anticipate an average season in terms of number of storms.
June is a rainy month in Japan and that coupled with the threat of typhoons creates more vulnerability for the crippled Fukushima reactors. Efforts are underway to weatherize the reactors against rain. Strong winds are not typically a concern when the already weakened storms reach Japan; but damaging winds – especially given the degraded state of the reactor structures – cannot be ruled out.
This news story from today relates that…”Tepco said on April 17 it will start erecting temporary covers for the damaged building within three months provided radiation falls to levels at which workers can begin construction. The work is expected to be completed in the next three to six months, according to the action plan, which lists the ‘possibility of the cover being damaged by a big typhoon’ as a risk.”
The work on the reactor covers will not be completed until much of the worst of the typhoon season is over. Anomalous years like 2004, which had a particularly intense season (below, from WeatherUnderground), make it seem even more important that the reactor stabilization plans be accelerated if possible.