Severe Geomagnetic Storm Alert: What Do Minnesotans Need To Know?

As the sun continues through the most active period of its multi-year cycle, a lot of extra energy bursts have been getting flung out into space.

Many of those less energetic bursts have led to some good Northern Lights viewing opportunities across Minnesota this year, but this particular space weather event is on a much rarer level.

A major burst of energy called a Coronal Mass Ejection (CME) erupted from the sun earlier this week, making its way right for Earth. Because of this, the Space Weather Prediction Center has issued a G4 Severe Geomagnetic Storm Alert.

Alerts at this level are pretty rare, with only a couple of them being issued in the last 20+ years. What does it mean for Minnesotans? Here's what you need to know.

What is a severe geomagnetic storm?

As explained by the Space Weather Prediction Center (SWPC), it is a major disturbance of the Earth's magnetic field.

These disturbances happen when things like CMEs erupt from the sun and make their way to Earth.

They vary in intensity, anywhere from a G1 (minor) geomagnetic storm to a G5 (extreme) storm. Extreme storms can have widespread impacts for people and technology.

What can we expect from the G4 Geomagnetic Storm forecasted for this week?

A G4 geomagnetic storm is the second to worst on the scale, labeled "severe" on their storm index.

Effects from a G4 storm, according to the SWPC can include the following:

• Power systems impacts: Possible widespread voltage control problems and some protective systems will mistakenly trip out key assets from the grid.
• Other impacts on the ground: Radio & satellite communications can be negatively impacted, GPS satellite navigation can be degraded, and infrastructure systems like pipelines can have currents induced.
• Auroras: Less impactful than the things above, a spectacular Northern Lights show can be expected well into the United States with KP Index numbers as high as 8 or 9.

As far as the potentially negative technology impacts go, infrastructure operators are notified of events like this to try to take mitigation actions, though that doesn't; mean impacts will be completely prevented.

READ MORE: These are scientifically speaking the best places for seeing the Northern Lights in Minnesota

When KP Index numbers reach levels like I mentioned, there are very high odds of seeing very active overhead Northern Lights throughout Minnesota and Wisconsin and as far south as places like Alabama and Northern California.

How long will this storm last?

The majority of impacts are expected on October 10 and 11, with the strongest effects expected as the CME reaches Earth on October 10.

How will the weather impact Northern Lights viewing?

With very high odds of a spectacular show like we saw back in May, the question of whether or not we'll have clouds to contend with is the biggest concern for those hoping to catch a show.

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Unfortunately, Thursday night does look to have some clouds moving in for the overnight hours. Depending on where you are, it isn't expected to be full-on overcast conditions for much of the state, but some cloud obstruction is likely Thursday night.

Friday night looks more promising for clouds. While the KP Index will be a little lower, the cloud situation should be, well, less cloudy.