Bad timing: Solar flares disrupted radio communications during September 2017 Atlantic hurricane relief effort

From the AGU:

WASHINGTON — An unlucky coincidence of space and Earth weather in early September 2017 caused radio blackouts for hours during critical hurricane emergency response efforts, according to a new study in Space Weather, a journal of the American Geophysical Union. The new research, which details how the events on the Sun and Earth unfolded side-by-side, could aid in the development of space weather forecasting and response, according to the study’s authors.

On September 6, three hurricanes advanced in a menacing line across the Atlantic Ocean. Category 5 Hurricane Irma ravaged Barbuda in the Caribbean’s Leeward Islands in the early morning and churned onward to St. Marin, St. Barthelemy, Anguilla and the Virgin Islands, causing massive damage. Tropical Storm Katia hovered in the Gulf of Mexico and Tropical Storm Jose approached from the open ocean. Both were upgraded to hurricane status later that day.

A huge solar flare flashes in the middle of the sun on Sept. 6, 2017. A separate image of the Earth provides scale. Credit: NASA/GSFC/SDO

On the surface of the Sun, 150 million kilometers (93 million miles) away, another storm was brewing.  A class X-2.2 and major class X-9.3 solar flare erupted on the morning of September 6 at about 8 a.m. local time.

NOAA’s Space Weather Prediction Center warned of a strong radio blackout over most the sunlit side of Earth, including the Caribbean.

Amateur radio operators assisting with emergency communications in the islands reported to the Hurricane Watch Net that radio communications went down for most of the morning and early afternoon on September 6 because of the Sun’s activity, according to the new study. French civil aviation reported a 90-minute loss of communication with a cargo plane, according to the study’s authors, and NOAA reported on September 14 that high frequency radio, used by aviation, maritime,  ham radio, and other emergency bands, was unavailable for up to eight hours on September 6.

Another large class-X flare erupted from the Sun on September 10, disrupting radio communication for three hours. The disruption came as the Caribbean community coped with Category 4 Hurricane Jose’s brush with the Leeward Islands and the Bahamas, and Irma’s passage over Little Inagua in the Bahamas on September 8 and passage over Cuba on September 9. Watch a video of the September 10 flare produced by NASA.

“Space weather and Earth weather aligned to heighten an already tense situation in the Caribbean,” said Rob Redmon, a space scientist with NOAA’s National Centers for Environmental Information in Boulder, Colorado, and the lead author of the new study. “If I head on over to my amateur radio operator, and they have been transmitting messages for me, whether it be for moving equipment or finding people or just saying I’m okay to somebody else, suddenly I can’t do that on this day, and that would be pretty stressful.”

Bobby Graves, an experienced ham radio operator who manages the Hurricane Watch Net from his home near Jackson, Mississippi, said the flares caused communications to go down for hours. The Hurricane Watch Net is a group of licensed amateur radio operators trained and organized to provide communications support to the National Hurricane Center during storm emergencies.

“You can hear a solar flare on the air as it’s taking place. It’s like hearing bacon fry in a pan, it just all of a sudden gets real staticky and then it’s like someone just turns the light completely off, you don’t hear anything. And that’s what happened this last year on two occasions,” Graves said. “We had to wait ‘til the power of those solar flares weakened so that our signals could actually bounce back off the atmosphere. It was a helpless situation.”

The new study detailing the activity on the Sun and its effects on radio communications from September 4 – 13 serves as an overview to a collection of journal articles inSpace Weather investigating the solar activity of September 2017. The collision of Earth and space weather in September delivered a reminder that solar events can happen at any time and may coincide with other emergencies, according to the study’s authors.

The information in the study could help scientists improve space weather forecasting and response, according to the study’s authors. By understanding how the events on the Sun and Earth unfolded, scientists can better understand how to forecast and prepare for future events, they said.

The new study shows the solar flares affected shortwave radio communications, which were being used by amateurs and professionals in emergency response efforts, although it does not detail how emergency efforts may have been affected by the radio blackout.

“Safeguards put in place to prevent dangerous disruption to GPS from solar events worked,” said Mike Hapgood, head of space weather at Rutherford Appleton Laboratory in the United Kingdom, and a scientist not connected to the new study. “In many ways, we were ready. Some things that could have caused big problems didn’t, but shortwave radio is always tricky to use during solar events. But good radio operators are aware of the events and will work hard to overcome problems.”

“It’s the Sun reminding us that it’s there,” Hapgood added. “The Sun’s been very quiet for the last 10 years. It reminds people not to be complacent.”

Unexpected space weather

The 2017 flares were the largest since 2005 and the best documented solar storm to date, observed from a fleet of spacecraft between the Earth and the Sun, in Earth’s orbit, on Earth and Mars.

Solar flares release bursts of X-rays from the Sun that travel outwards in all directions at the speed of light. Strong flares can disrupt radio and aviation communications. Space weather forecasters have only minutes to broadcast warnings to spacecraft, aviation and other administrators before affects are felt on Earth.

X-rays from solar flares interact with Earth’s atmosphere 50-1000 kilometers (30-600 miles) above the Earth, in a region called the ionosphere. Shortwave radio communication works by bouncing signals off the ionosphere and refracting them back to Earth. When the Sun releases a burst of x-rays, like the flares released in early September, the extra energy delivered to the ionosphere can cause it to absorb high frequency radio signals, like those used by ham radio enthusiasts.

The September 6 and 10 flares were also accompanied by bursts of high energy solar material explosively ejected from the Sun in an expanding bubble much larger than the Earth. Such coronal mass ejections, which arrive within one to three days, have the potential to wreck the most havoc on human technology. The geomagnetic storms generated by coronal mass ejections can damage power grids, confuse GPS systems and damage or disrupt communication with spacecraft, including weather satellites.

NOAA’s Space Weather Prediction Center issued warnings for potentially severe geomagnetic storms for September 7-9.

An unlucky coincidence

The unexpected burst of space weather coincided with high hurricane activity in the Atlantic Ocean.

Irma, one of the most powerful Atlantic hurricanes on record with sustained winds of 287 kilometers per hour (175 miles per hour), hit the tiny island of Barbuda at maximum intensity, razing 95 percent of its buildings. The storm destroyed most homes and much infrastructure on St. Martin, Anguilla, Great Inagua and Crooked Island in the Bahamas, and the U.S. and British Virgin Islands. It caused power outages and damage in the Cuban Keys, Turks and Caicos and the southeastern United States. Wind and rain from the storm killed 37 people in the Caribbean and 10 on the U.S. mainland, according the National Hurricane Center.

During the September crisis, the Caribbean Emergency and Weather Net logged many “radiograms” relaying survival notes between anxious family members on the islands and the mainland via ham radio operators, Redmon said.

“Seeing that logbook really brought home to me the human dimension of the storm,” Redmon said. “It put the humanity in the science.”

Ham radio hobbyists routinely volunteer to disseminate hazard information from the National Weather Service to island communities and ships during major storms, report real-time ground conditions and damages back to the National Hurricane Center, and assist the Red Cross with communications.

Graves, the ham radio operator, said many people trapped by storms appreciate hearing a friendly voice over amateur radio relaying the latest weather update, even if they are not able to reply. During a storm, ham radio volunteers strain to listen for lone stations in the affected area that may still be transmitting, Graves said.

“A lot of folks in the area were asking us: We heard there’s Jose coming behind Irma, what’s this thing going to do?” he said.


0 0 votes
Article Rating
Newest Most Voted
Inline Feedbacks
View all comments
July 30, 2018 12:25 pm

It’s been a very long time since I was a radio amateur. That said, my first thought was to wonder about the amateur radio satellites. link

Holy moses there have been a lot of amateur radio satellites since 1961. A bunch are currently operational. Amazing the stuff that happens when your back is turned and you aren’t paying attention. 🙂

Reply to  commieBob
August 1, 2018 1:55 pm

I, for one, would like to welcome you back! There are many more “modes” to operate today, including my favorite mode, WSPR. WSPR is ideal for ‘plumbing the depths’ of radio propagation and also parametrically measuring one antenna’s performance against another and yielding REAL ‘engineering’ numbers in decibels.

July 30, 2018 12:55 pm

Kind of sobering…

How reliant we are on amateur radio to provide all kind and nature of emergency services. And for the most part, the whole network of gear-heads operating their various amateur band transceivers are UNPAID for their services, for their skill, their craft, their adherence to The Rules, and their fraternal helping of each other. Rather amazing. Like a volunteer-run fire department, with volunteer-provided trucks, lunches, hoses, with volunteer-maintained water mains, fire roads, ambulance services.

Wait… we don’t have those entirely.

But we have HAM Amateur Radio. And have since the 1920s. Renews ones faith in Humanity, doesn’t it? Just saying… GoatGuy

July 30, 2018 12:55 pm

the magnetic storm impact was some 36h later concentrated during the night of 7-8 September 2017
800-900 nT is about 50-75% more intense than an average geomagnetic storm.

Curious George
July 30, 2018 1:16 pm

“Two generally important lessons learned from this period include the need to continue improving forecaster access to operational,real-time coronagraph imagery (for solar ejecta monitoring), and the value of direct communication between forecast centers and customers during important space weather events to increase the awareness of space weather and technological impact causality.”

Overall impression: they need more funding.

Lurker Pete
July 30, 2018 1:25 pm

In the UK we have RAYNET which took over from the old Radio Amateurs’ Emergency Network and the Radio Society of Great Britain at the end of 2016 and is now the UK’s only national voluntary communications service provided for the community by licensed radio amateurs and other supporting volunteers.

Anyone wondering what all this ‘Amateur Radio’ stuff is all about check out ‘WebSDR’ which is a software defined radio connected to the internet, you can browse the airwaves in the amateur bands without the expense of buying and setting up a radio yourself!

There’s fairly decent list here:

Reply to  Lurker Pete
July 30, 2018 5:37 pm

Recommended frequency this time of evening/night would be 3.916 MHz if in the southern/central part of the US.

Look for the Birmingham Alabama SDR for starters, too.

July 30, 2018 1:33 pm

I would like to know at what frequencies solar flares produce noise? The only indication in this article was “high frequency radio signals”. Is that actually the HF band?

Reply to  Jeff in Calgary
July 30, 2018 2:32 pm

HF (3 to 30 MHz) propagates off the ionosphere and solar storms make the conditions at that level of the atmosphere completely useless for propagating waves. It is the frequency used in long range maritime and aeronautical communications particularly before the widespread advent of satellites. Of course solar storms are a double whammy as the satellite operators tend to put their charges in self-defense mode at the same time that HF propagation goes to heck. This is also a very popular HAM band as the equipment is pretty simple to put together. The VHF band is another popular HAM band, but it isn’t good for long range comms because it is mostly line of sight (with some sky-wave return and surface-wave bending). It is good for local distribution coordination in an emergency situation, but doesn’t have the hemispheric or global reach of a strong HF signal.

My best HF radio check was from a C-130 at Keesler AFB MS to an operator in Canberra Australia. The sky was perfect for it at 4:30 AM central time doing maintenance pre-flight comm checks before a Hurricane mission.

Juan Slayton
July 30, 2018 2:21 pm

Anybody know to what extent Caribbean islands have repeater networks that can propagate by near line of sight? I recently returned to an old hobby after many years of absence, and am surprised that repeaters seem to be a big thing now.
Juan Slayton

Reply to  Juan Slayton
July 30, 2018 2:36 pm

Repeater networks were in place, but high winds tended to take them out and those that survived had no power. It is one of the things the on-the-ground people try to get up first so they can coordinate local relief.

D. J. Hawkins
July 30, 2018 2:46 pm

I have to kind of shake my head and smile at the “forecast and prepare” statement. Is that “prepare” the same sort of “prepare” some wags suggested in the event of nuclear war? “Put your head between your legs…” After all, when the flare scrambles the ionosphere, what “prepare” can you do??

Reply to  D. J. Hawkins
July 30, 2018 7:47 pm

If you can forecast (far enough ahead, that is) – you can prepare. Death tolls from storms were much higher before forecasts became available, even imperfect as they are about the track the storm will take. (Worse even than the raw figures, if you consider deaths per capita for the population at the historic time.) Property damages were also much higher when viewed as the percentage of the property value lost.

D. J. Hawkins
Reply to  Writing Observer
July 31, 2018 12:01 pm

In this context, they are talking about the interruption of communication. What preemptive measure can you take to prevent that?

Reply to  D. J. Hawkins
July 31, 2018 12:20 pm

Plan for the use of alternate wavelengths, i.e., using 160 meters rather than 80 meters esp. in the mornings … but this can call for planning e.g, having an effective 160 meter antenna in place before the event happens.

July 30, 2018 3:19 pm

Aren’t this the exact same people who have been telling us for years that the “sun” has absolutely no effect on climate or weather? Or HAM radio reception or propagation? Are these not the same liars who keep changing their names whilst LYING TO US all the time? Why is anyone listening to these liars?

July 30, 2018 4:15 pm

Showing my age here. As a weather observer for Environment Canada back in the Spring of 1978, I was on a temporary posting to Dease Lake, BC while one of the regular guys was away on a course. This was before cheap satellite, or “the web”, or full-fledged automated weather stations. Hourly weather observations were radio’d in. For “entertainment” I took along a good portable shortwave radio. Amazing the reception you’d get on BBC ABC (Australia), Radio Papua New Ginuea, etc when you’re out in the middle of nowhere, with very little electrical interference.

I remember a stretch of a few days when my shortwave radio, normally very good, got absolutely nothing. I was wondering if it was broken. However, we weren’t able to contact our relay station (Watson Lake; not sure) via radio, so I figured it was a solar storm.

July 30, 2018 5:33 pm

Article:: “Shortwave radio communication works by bouncing signals off the ionosphere and refracting them back to Earth.

So does MF (Medium Wave) during ‘nighttime’ hours anyway. MF encompasses 160 meters (1.8 thru 2.0 MHz) as well as the AM broadcast band…

I mention this for completeness and also because _so_ much of the ham community overlooks the utility of 160 meters in the early morning hours when propagation is ‘long’ on 80 and 40 meters and therefore useless for in-theater (Zero to 300 miles) NVIS comms at a time when 160 meters shines for this purpose. Comms relying on NVIS (Near Vertical Incidence Skywave) are where signals are bounced off the ionosphere nearly ”straight up’ or at small value angles from straight up.

I made a study of prop (propagation) on 160 meters versus 80 meters the last couple of years as my one working eye slowly went bad , observing the Austin, Texas Ionospheric sounder as it measured the reflective height of the ionosphere from 1.8 MHz or so up through 20 MHz while observing conditions on 80 meters. At that same time I also worked a number of stations in and around Texas from a small city-sized lot on 160 meters demonstrating that is does not require acres of land to erect and successfully operate a station on 160 meters.

Perhaps if the agencies, individuals involved in wireless comms made use of a wider range of frequencies, like the 160 meter MF band they could have established those critical comms.

BTW, here is a link to the Austin Tx ionograms for 6 Sep 2017 which shows the ionosonde data taken every five minutes:

Joel O'Bryan
July 30, 2018 6:06 pm

Those flares did more than just juice-up the ionosphere. And the timing of the flares was just prior to NH autumn equinox. Putting the sun straight-over the NH tropics band.
Those flares punched the stratosphere hard with elevated EUV and UV.
Remember, the stratosphere’s temperature profile, warmer as you go up, is due to stratospheric ozone intercepting all the EUV and most of UV, and turning that EM energy into heat.

These EUV/UV blasts, occurring at peak Atlantic hurricane season, did two things.

– In the short-term, those flare’s energy immediately warmed the stratosphere, and thus lowered the tropopause. This allowed Irma to strengthen as it was better able to connect its cumulo-nimbus heat towers to a slightly lower tropopause. This improves its energy transfer efficiency and power output — a stronger hurricane.

– The EUV pulses pumped up the ozone concentration in the stratosphere, which is a longer term effect that takes several months to fall back to the normal range. Elevated ozone concentrations in the stratosphere helped maintain an elevated lower stratosphere temperature profile, which again kept the tropospause altitude slightly suppressed. This continued to aid tropical storm development and strengthening, including Maria which devastated PR on Sept 20, and as a Cat 5 monster hitting Dominica on 18 Sept.

Rainer Bensch
July 31, 2018 2:03 am

solar flare erupted on the morning of September 6 at about 8 a.m. local time

surely they give local solar time… but what does ‘morning’ mean? 😉

Reply to  Rainer Bensch
July 31, 2018 5:31 am

Same question here – I may have to go read their report after all …

Russ Wood
July 31, 2018 9:19 am

E M Smith ( wrote a while back that all cell phones are effectively short range transmitters and receivers. Why isn’t there some way of turning them into sort-of walkie-talkies? This would be invaluable in case of a civic emergency, when power goes out and the cell towers aren’t working. Last year, there was a major fire around and inside a South African seaside town, Knysna. The power lines went down, the cell towers burned, and comms was out. A major problem turned out to be co-ordination of the professionals and volunteers. Anyone know if this has been approached by any of the cell manufacturers – or is it all to do with government licencing?

Reply to  Russ Wood
July 31, 2018 3:03 pm

Q: “Why isn’t there some way of turning them into sort-of walkie-talkies?

Standards agencies (EIA/TIA in the USA) don’t see any benefit to themselves in such a mode, and neither does the FCC (again, in the USA) _who_ could mandate such functionality (come to think of it.)

On the legal side,USA allocations of the spectrum for the use of such devices is to the __carriers__ (e.g. T-Mobile, ATT, Sprint etc) and _not_ to the public or subscribers themselves, so itinerant operation is verboten.

On the technical side, USA “cell phones” work in a full duplex mode with different frequency bands within each cell or PCS allocation and these devices are therefore not capable of simplex or unit to unit communication without the aide of a “radio repeater” or cellular base station. Normally these subscriber’s receivers and transmitters use frequency specific band pass filters and duplexers in their circuitry which do not allow simplex RX and TX.

There are some wireless equipments that work on a simplex basis, e.g. WiMax -but- that protocol works instead on TDD (Time Division Dulplex) mode and the base stations in that service use GPS to synchronize themselves such that all BS radios transmit at the same time and do not “step” on the assigned subscriber radio time slots.

%d bloggers like this: