On March 17, 2015, which also happens to be St. Patrick's Day, the strongest geomagnetic storm of Solar Cycle 24 occurred following a coronal mass ejection (CME) impact. This page provides data and imagery regarding the event as it unfolded.|
On March 15th, 2015, A sunspot numbered 2297 which had been responsible for a number of moderate M-Class solar flares and one X-Class event, produced a long duration C9 solar flare at 02:13 UTC. While a C-Flare might not typically grab much in the way of attention, the magnetic characteristics of the eruption caused a partial halo coronal mass ejection (CME) to be flung into space and appeared to have somewhat of an Earth directed component. A minor impact past our planet was predicted for late on Tuesday, March 17, 2015.
On March 16th, 2015, Energetic proton levels streaming past our planet were on a gradual rise, an early indication that an interplanetary shock wave was on course with our planet.
At 04:05 UTC on March 17th, 2015, an earlier than expected shock passage was detected by the ACE spacecraft. Solar wind speeds as measured by ACE increased to above 500 km/s, while the Bz component of the interplanetary magnetic field (IMF) was initially pointing north, a condition known to suppress geomagnetic activity.
Half an hour later at 04:35 UTC, a geomagnetic sudden impulse measuring 54nT was recorded by the USGS ground based magnetometer in Boulder, Colorado. This signaled the moment the interplanetary shock wave (coronal mass ejection) swept past our planet. Initially conditions did not look favorable, however the Bz/IMF component soon began to point sharply south for long periods (-23nT peak). This allowed an energetic solar wind to interact with our geomagnetic field, thus leading to what I am calling the St. Patrick's Day Storm of 2015. Over 24 hours of storming, a majority of which was above moderate levels, led to incredible aurora displays at middle to high latitudes. Ham Radio Operators located across northern tier sections of Europe and North America utilized geomagnetic activity enhancements which is known to reflect signals in the very high frequency (VHF) radio spectrum. Because of the long duration of the event, sky watchers from Europe, Canada, northern tier sections of the USA, New Zealand and even Australia were able to witness some of the best aurora displays in years.
Below is detailed imagery data regarding the event.
Aurora Photography Captured During the Storm.
Thanks for reading and I hope you enjoyed this presentation regarding the St. Patrick's Day 2015 Geomagnetic Storm.