Scientists at NCEI are studying solar activity and tropical cyclones from the first week of September 2017, when overlapping events brought about severe consequences. Researchers want to expand the scientific and practical knowledge of solar impacts. In this case, bad timing increased the vulnerability of several Caribbean communities.
“Space weather occasionally occurs in tandem with extreme terrestrial weather,” according to scientists from NCEI, Cooperative Institute for Research in Environmental Sciences (CIRES), and other institutions in an open access Space Weather journal article. “When it does, the struggle to mitigate the impacts to life and property can be dramatically intensified. This one-two punch landed on the socioeconomically and technologically diverse communities of the Caribbean islands during the September 2017 hurricane season.”
[Solar active region AR12673 erupted several times September 3–10, 2017. AR12673 is circled in far left image. The region moves to right as sun rotates away from Earthward direction. The September 6 solar flare caused high-frequency radio blackouts on Earth during Hurricane Irma. Courtesy of NOAA NCEI.]
In the Caribbean, the subsequent radio blackout disrupted high-frequency ground communication and aviation systems when emergency needs were critical. An official for the Hurricane Watch Net (HWN) said the outage caused a near-total communication blackout for most of the morning and early afternoon of September 6. French Civil Aviation Authority officials reported losing contact with an aircraft in the region for 90 minutes during the blackout, triggering an alert.
The hurricanes and the solar disruptions didn’t end with Irma. Hurricane Jose followed, and AR12673 remained active. In total, the active region fired off four X-class flares, the largest flare classification. Collectively, AR12673’s explosive events between September 4–10 were the most energetic of the current solar cycle, which started in December 2008 and is nearing its end. The events also elevated the risks of radiation exposure to astronauts, disruptions to space instrumentation, and long-term satellite damage.
Hurricane Irma caused many fatalities and severe economic damage in the Caribbean and the United States.
[A forecaster‘s timeline. SWPC and other forecasters are always watching for solar events as potential predictors of near term technological impacts. This diagram provides a rough phenomenological timeline from X-ray and radio noise producing flares (top) to energetic particles (i.e., SEPs of both eruptive and CME origin) and the arrival of CME solar plasma. Watches, warnings and alerts are invaluable tools for forecasters to disseminate critical space weather information. Adapted from SWPC‘s ―Time Scale for Solar Effects. From NOAA]