Geomagnetic Storms Bring Widespread Northern Lights to U.S.

Geomagnetic storms on Tuesday night resulted in the visibility of the Aurora Borealis across a significant portion of the United States. Observations were reported in states including Idaho, Iowa, Missouri, New Mexico, New York, Oklahoma, South Dakota, Tennessee, Texas, and Washington. The northern lights were also visible as far south as parts of Florida and Alabama.

Understanding Geomagnetic Storms

A geomagnetic storm occurs when charged particles originating from the sun's atmosphere interact with Earth's magnetic field. These storms have the potential to disrupt various technological systems, including satellites, GPS, radio communications, and electrical power grids.

The activity on Tuesday was attributed to coronal mass ejections (CMEs), which are large expulsions of plasma and magnetic field from the sun's outer atmosphere that travel towards Earth. Two CMEs reached Earth on Tuesday.

Storm Intensity and Forecast

The resulting geomagnetic storm reached G4 levels, which is the second-highest classification on the National Oceanic and Atmospheric Administration's (NOAA) five-step scale. Forecasters anticipated the arrival of a third CME by midday Wednesday, projected to be more intense than the preceding two.

The Space Weather Prediction Center indicated that the aurora might become visible "over much of the northern half of the country, and maybe as far south as Alabama to northern California." The U.K.'s Met Office also suggested potential aurora visibility over parts of Britain on Wednesday night, subject to cloud cover.

Viewing and Photography Guidelines

To observe the aurora, a dark environment away from light pollution is essential. Optimal viewing times are generally between 10 p.m. and 2 a.m. local time.

Several resources can assist in tracking aurora visibility:

• Aurorasaurus: A citizen science platform where users report aurora sightings and access visibility estimates.
• My Aurora Forecast & Alerts app: A location-based application providing viewing probability and forecasts for iOS and Android devices.

Smartphone cameras often capture a broader spectrum of aurora colors than the human eye. Utilizing a phone's night mode or adjusting manual exposure settings can enhance photographic results.

Increased Aurora Frequency

The recent increase in aurora occurrences in the United States is linked to the sun approaching the peak of its 11-year cycle, known as the solar maximum. This period is characterized by an elevated frequency of solar eruptions, which release electrically charged particles (ions) towards Earth, forming what is known as solar wind.

As these charged particles from the solar wind approach Earth, they collide with gases in the planet's atmosphere, leading to the emission of light at various wavelengths, which produces the colorful displays. During the solar maximum, the heightened solar activity expands the typical aurora viewing areas beyond the Arctic Circle.