Radio Black Out: Extreme G5 Geomagnetic Storm!
We had a near radio black out on the 40m band at around 6.55 am local time (0125z). We were having our regular roundtable on 7050 kHz, with several stations coming in at 5,9+20dB. All of a sudden all stations beyond 200 km disappeared from the screen. Nearby stations could contact each other with great difficulty. Prior to that even stations at 1300 km were coming in well. My usual first source of information is Twitter (X) and I found posts on G5 Geomagentic storm. The United States National Oceanic and Atmospheric Administration Space Weather Prediction Center post mentioned that Extreme (G5) geomagnetic conditions have been observed. G5 is the strongest on a scale from G1 to G5. It is likely to persist through out the weekend as several Earth directed Coronal Mass Ejections (CME) are in transit from the Sun. The area which is causing these flares, a large complex sunspot cluster, has a diameter almost 17 times of the Earth!
It has been predicted that HF, VHF, UHF communications, GPS, power grids, spacecraft and satellite navigation may be affected. There was news that transpolar flights have been cancelled or diverted. Luckily, I was able to have a contact through the Amateur Radio on International Space Station about 20 minutes prior to the radio blackout which we noted on 7 MHz amateur radio band. The single feeble waterfall seen here is a station within 200 km, which usually has a dense waterfall at that time.
Radio communications improved a bit about 50 min into the event with couple of nearby stations coming up on the waterfall display. Normally it is a busy time here on 40m with at least 5-6 waterfalls with local roundtable chats going on. There is a net going on at 7080 kHz, but most of the stations are quite feeble and barely audible, with no signal on the waterfall display. The last G5 Extreme Geomagnetic Storm occurred in October 2003 causing power outages in Sweden and damaged transformers in South Africa. Ham Radio Science Citizen Investigation (HamSCI) Google Groups, which I am member of, was flooded with messages. Several hams reported seeing aurora across the United States and even from Chile.
Additional solar flares, including X-class flares which are the most powerful class of solar flares are expected over the weekend. NOAA has mentioned that a solar radiation storm could expose people in high-flying aircraft to elevated radiation risk. Radio black outs have been grade on a scale R1 (minor) to R5 (extreme). There is a mention of R3 Radio blackout being detected. At that level, wide blackouts of HF radio communication with loss of contact for about an hour on the sunlit side of the Earth is expected. That is exactly what we observed here in South India today morning, starting nearly an hour after sunrise!