Javascript is disabled on this browser.
Javascript must be enabled for this website to display and function correctly.

Space Weather Alert - 10-11 September 2014

What Has Happened?


SOHO image of the corona. Image SOHO (NASA/ESA)

Plot of the X-ray flux showing the M and X-class flares on 9th and 10th September. Image NOAA/SWPC.

Image of the Sun's magnetic field. Image SDO/NASA.

A Coronal Mass Ejection (CME) was observed leaving the Sun during the early hours of Tuesday the 9th of September. This CME was associated with a long duration M Class X-ray flare (M4.5) which began late on the 8th of September and peaked at 00.29UT on the 9th.

The CME appears to be primarily directed northwards, however we still anticipate sufficient interaction with the Earth's magnetic field to increase global geomagnetic activity.

We expect the CME to arrive around midnight or during the early hours of Friday the 12th of September. This is likely to enhance geomagnetic activity with probable periods of storm conditions throughout the day.

****** STOP PRESS! *******

A second CME was observed on 10th September, associated with a more powerful X1-class flare from near the centre of the Sun. This CME is expected to arrive during 12th September, possibly only shortly after the first CME.

Due to the combined effects of both CMEs there is a good chance of stormy geomagnetic conditions throughout the next few nights.

Assuming clear dark skies, there is an increased chance of seeing the aurora, particularly in northern parts of the UK, after the arrival of the CMEs. The best chance will be Friday night with a possibility of further aurorae on Saturday.


Sign-up to receive Geomagnetic Disturbance Alert emails.


Follow us on Twitter:

for more occasional aurora alerts.

for daily space weather forecasts.



The British Geological Survey is one of the Natural Environment Research Council's Research Centres.

CME or Coronal Mass Ejection
The eruption of a portion of the outer atmosphere of the Sun into space, caused by rapid changes in its magnetic field. Often occurs along with a solar flare.

Solar Flare
Energy released by the explosive reorganisation of magnetic fields within the Sun's atmosphere.

Solar Wind
The ever-present expansion of the Sun’s hot outer atmosphere into the solar system, which carries space weather within it.

A region of intense magnetic field in the Sun's visible outer atmosphere often associated with flares and CMEs.