The aurora in Fairbanks, Alaska, on Monday night. (John Chumack via spaceweather.com)

Update at 12:45 p.m.: According to forecasters at the Space Weather Prediction Center, the geomagnetic storm continues on Tuesday afternoon, sporadically peaking at G4 intensity on the five-point scale. The severe geomagnetic storm was probably caused by the combination of two coronal mass ejections from an active sunspot region, the center’s forecasters said in a teleconference. Space weather models predicted just a “glancing blow” from these ejections, which instead have caused a stronger disruption here on Earth, and vivid auroras that have been seen as far south as Michigan.

Sightings of the Aurora Borealis, commonly known as northern lights, were reported across Europe including near Penmon Point, Wales. (CJ Barr via YouTube)

The Space Weather Prediction Center has received no reports of negative impacts thus far, and there are no indications of a radiation storm that would impact satellite electronics and high-latitude flights. However, there could be some disruption in GPS technology and satellite navigation.

[New satellite DSCOVR to monitor solar winds]

While the forecast remains highly uncertain, space weather forecasters suspect the storm has reached its maximum intensity. But there is potential for the storm to continue at this magnitude after dark on Tuesday. “We’ve seen, I think, what this [storm] is capable of, but we can’t tell you that with certainty,” said Bob Rutledge, lead forecaster at the Space Weather Prediction Center. “We have the potential for similar conditions over the next 12 hours, after which we could see some decay.”

(Univ. of Alaska Fairbanks)
Aurora viewing forecast for early Tuesday afternoon. Should the magnitude of the geomagnetic storm continue into the evening, it’s possible that sky-watchers in the D.C. area could see the aurora on the horizon in dark locations. (Univ. of Alaska Fairbanks)

Should the geomagnetic storm continue at its current intensity into the evening, locations in the middle U.S. — and even the D.C. area — could have the opportunity to see the aurora on Tuesday night. In previous geo-storms of this magnitude, “we have seen reports of aurora as far south as Tennessee, New Mexico, and Oklahoma,” said Brent Gordon, the center’s branch chief. “A lot of factors go into whether you can see the aurora, cloud cover most importantly, and proximity to city lights. We are favorable in terms of the moon being crescent, which will give us pretty dark skies.”

[D.C. area forecast: Skies clear tonight after cold front]

Here in the D.C. area, skies are expected to clear out behind the afternoon cold front, which means — if the storm continues at its current intensity — sky-watchers in the darker, rural parts of our area could get a chance to see the northern lights on the horizon.

Original story:

A severe geomagnetic storm is whipping through Earth’s magnetosphere, causing disruption to power systems and spawning a beautiful green, St. Patrick’s Day-themed aurora that stretched as far south as Oregon and Illinois.

The storm, which began late Monday as a weak G1 intensified Tuesday morning, climbing to a G4 on the five-point scale, according to the Space Weather Prediction Center. It’s the fourth G4-magnitude storm in the current solar cycle, and is “in-season,” so to speak, since they are most common around the equinoxes.

As of 10:30 a.m. Tuesday, the storm’s K-index has reached K8, which suggests that if it were dark out, the southern edge of the aurora could be seen as far south as Pennsylvania and Ohio, Iowa, Nebraska and Oregon. It’s possible the aurora could even be seen in the northern D.C. area — if only it were dark!


A map of K-index across the Northern Hemisphere, which shows how far south the aurora can be seen as the geomagnetic storm gets more intense. Tuesday’s storm has a K-index of 8. (NOAA)

According to our contributing space weather expert, Joe Kunches, the solar wind is not particularly fast, but it’s potent enough to cause the severe geomagnetic storm. It’s possible that polar flights — like those on their way from the eastern United States to Asia — may prefer a more southerly route to maintain communications. Other common impacts such as satellite orientation issues and spurious power grid currents also are possible during the storm.


The aurora in Donnelly Creek, Alaska, early Tuesday morning. (Sebastian Saarloos via NASA Goddard)

In far northern Alaska on Tuesday morning.”Never saw anything like this,” said the photographer. (Marketa Murray via spaceweather.com)

Near Fergus Falls, Minn. (RPJs Photography via spaceweather.com)

The Milky Way and the aurora in Haystack Mountain, Alaska. (Dirk Obudzinski via spaceweather.com)

Chester, S.D. (Christian Begeman via spaceweather.com)

Washington, Ill. (Kevin Palmer via spaceweather.com)
(via @DJHardwired)
The aurora around 12:45 a.m. in Bulyea, Saskatchewan, Canada. (@DJHardwired)

An earlier version of this story said that this was the strongest geomagnetic storm of the current solar cycle. The Space Weather Prediction Center has confirmed to the Post that it’s the fourth G4 storm in Solar Cycle 24, but cannot confirm that it’s the strongest.