Category Archives: Solar Storm Recap

Early March G2 Aurora Strom Puts on a Global Show

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Northern Lights Now – An extended period of high solar winds, the result of a large Earth-directed coronal hole, put on a three day long show for aurora hunters in high latitudes in early March. Photographers captured aurora glows, pillars, picket fences, dancing displays and illuminated night landscapes from around the world between mid March 1 through early March 4. Here’s a spectacular time lapse video from Adam Hill showing a wave of northern lights racing westward through the sky.

This extended storm was measured by the Space Weather Prediction Center (SWPC) as 9 periods of G1 storming and one period of G2 storming over 66 hours. G1 storming means the KP reached 4.67 and aurora can be visible as far south as Toronto, the upper midwest in the United States, Seattle and Scotland and can be seen as far north as Invercargill and Tasmania in the Southern Hemisphere. G2 storming means aurora can be seen at even lower latitudes near cities such as Portland, Boise, Dublin, Hamburg, Moscow and Christchurch. This chart show the first 5 days of March with the G1 and G2 3-hour periods showing in Red.

5 days of geomagnetic activity as measured by NOAA and SWPC
5 days of geomagnetic activity as measured by NOAA and SWPC

This early march storm is the result of a coronal hole that was pointed towards earth at the end of February. The hole is shown as a dark area on AIA 193 in the image below. It exposes the high speed solar wind emanating from the solar surface. Here’s an image of the coronal hole from the Solar Dynamics Observatory:

Coronal hole in AIA 193 shown as a dark finger reaching up toward center disk from the pole
Coronal hole in AIA 193 shown as a dark finger reaching up toward center disk from the pole

Those high speed solar winds take 2-5 days to arrive at Earth, and when they do they push on the magnetosphere and can cause aurora. This means that when there is a coronal hole pointed towards Earth solar scientists can predict that there is a good chance for activity 1-3 days in advance. Watch for those predictions on the NLN 3-day aurora cast – potential G1 storming shows as orange on those charts.

Let’s enjoy the view! Here are a few of our favorite tweets from this storm:

Watch the cloud clear and the lights come out to play in this time lapse

Stan’s take shows the aurora in black and white – this really brings out the texture and shapes

This panorama is worth clicking on and viewing full screen!

Finally, one of our favorite types of aurora – the “Picket Fence”

If you would like to have a chance to see the northern lights in person, consider following the NLN twitter feed (@northlightalert) to learn more about why aurora happen and when they may be visible.

Update #2: Mid-October Aurora Reached G2 storming, G3 predicted

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Northern Lights Now – The predicted G1, then upgraded to G2, aurora predicted for October 13-15 is meeting and exceeding expectations. KP values recorded in 3-hour increments by the airforce and SWPC were registering between G1 and G2 for much of the day. KP predictions from the Wing-KP model ranged from 4.67 to 7.67 from Noon GMT through Midnight GMT. SWPC has upgraded the watch level on the 14th to G3. Storming will likely only reach that level if the storm continues to intensify – and there have been some hints that it is starting to wane. Here is the chart showing today’s recorded geomagnetic activity:

Global Geomagnetic activity recorded on Oct 13 in 3-hour increments
Global Geomagnetic activity recorded on Oct 13 in 3-hour increments

At the peak of today’s storm the Bz had rotated powerfully to the south, registering as much as -20 nT. This is some of the strongest negative orientation of the Bz since the Saint Patrick’s day storm of 2015. In addition to being strongly south, the field maintained that orientation for a long time. As of this writing, the Bz had been negative for almost 20 hours. This is the longest duration negative Bz since NLN started producing this graphic that shows the duration certain important thresholds for aurora have been exceeded:

NLN Solar Wind Charts show long duration and powerfully south oriented Bz and strong Bt too
NLN Solar Wind Charts show long duration and powerfully south oriented Bz and strong Bt too

With a storm this strong, we’d normally expect to see many wonderful aurora pictures rolling in from our readers and aurora hunters. However, there were a lot of clouds in the normal viewing locations. In NLN’s HQ city of Burlington Vt it was raining most of the day and is cloudy this evening. The Moon is also nearly full, currently at 94% visible, and is washing out the aurora for people who have clear skies. That isn’t stopping photographers, and there are a few beautiful pictures rolling in. Here are a few. Please tag @northlightalert in your photos if you’d like to have them featured in the NLN blog!

Ontario got in on the action:

And upstate New York in Rochester:

Behind a tractor in Wisconsin:

Just a hint from Ireland:

Early September Aurora Lights Up The Sky

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Northern Lights Now – A long duration geomagnetic display gave aurora hunters a treat on the first three nights of September. Space weather conditions, under the influence of a large coronal hole on the Sun, were favorable for aurora borealis from late August 31st through September 3rd. KP reached G2 (moderate) storming levels for four 3-hour periods during that time. Strong storming is expected to continue for another 6-12 hours

Storm Origins

September’s solar storm was caused by strong solar wind buffeting Earth. The solar wind is the stream of charged particles constantly flow outward from the Sun into the Solar System. At Earth, that stream travels at about 350-400 km/s under normal conditions. This weekend it has been flowing at 600-750 km/s. The magnetic fields of those particles interact with, and push on, the magnetic fields of Earth. Solar wind becomes enhanced as the result of CMEs or when coronal holes are pointed towards Earth.

The current enhanced solar winds are from a very large coronal hole in the northern hemisphere of the sun. It is visible as the dark area from AIA211 images taken by the SDO satellite:

Large Coronal hole pointed towards Earth on August 31st
Large Coronal hole pointed towards Earth on August 31st

Long durations

Also visible in the above photograph is the longitudinal extent of the hole. As the Sun rotates, it takes about 14 days for a feature to move from the east lime (left side) to the west limb, the different portions of the hole are pointed towards earth. The longer portions of the hole are pointed towards Earth, the longer high solar wind speeds will impact earth and the longer the potential storm is. In today’s DSCOVR solar wind chart, notice that wind speeds have now been above 500km/s for over 48 hours, and above 650 km/s for over 6 hours:

Solar wind speeds have been strong for over two days
Solar wind speeds have been strong for over two days

The result of that long duration wind stream has been an epic solar storm. Over the last three days there have been four 3-hour periods where Boulder KP readings exceeded G2 storm levels, nine periods exceeded G1 levels and just 4 periods of KP less than three.

Three days of extrodinary aurora storming as measured by SWPC in Boulder Co.
Three days of extrodinary aurora storming as measured by SWPC in Boulder Co.

The Good Stuff

Below find several of our favorite tweets of pictures from this storm

A back of cam pic from the beginning of the storm in Finland:

The next night in Wisconsin:

Tasmania!

This Full sky display from over Lake Superior:

And of course, this author went out hunting in Colchester VT because we had clear skies:

More To Come

The official forecast shows this storm slowly decreasing in strength over the next 6-12 hours. There is still plenty of possibility for yet another night of display for Europe and the Eastern half of N. America. As long as wind speeds main enhanced, any disturbance traveling on the high speed wind stream could set off another substorm.

Happy Hunting