Weathercatch: When and why the northern lights dazzle our region’s skies

Eighteen years ago this month, the sun spewed giant plumes of electrically charged particles toward earth at more than a million miles an hour. The result was a geomagnetic storm that led to a brilliant northern lights display over the Inland Northwest.

The phenomenon, known scientifically as the aurora borealis in the Northern Hemisphere, is typically visible closer to the north pole in locations such as Alaska, Canada and Scandinavia. But during the late-night hours of Nov. 7-8, 2004, the shimmering lights spilled over to Washington.

The unusual light show also was witnessed as far south as Alabama, although its appearance wasn’t nearly as vibrant as in our region. “Spectacular” is how the National Weather Service in Spokane described the shimmering lights over the Inland Northwest.

The memorable display demonstrated how space weather such as sun spots, solar flares and storms can impact the earth’s atmosphere. Even though the sun is 93 million miles away, disturbances on its surface can have far-flung effects. According to NASA, the stellar show in 2004 was the result of an intense geomagnetic storm generated by a series of major eruptions that occurred on the sun a few days earlier. Energized solar particles were hurled into space, ultimately interacting with the earth’s magnetic field and creating dancing waves of light.

Here on earth, weather conditions helped determine how visible they were. Under mostly clear skies and a late-rising crescent moon, the Inland Northwest was a prime viewing spot. For sky-watchers huddled outdoors near midnight, it helped that temperatures ran several degrees above normal for early November.

Space weather, like weather on earth, is constantly unfolding and shifting – something we earthlings are generally unaware of until the northern lights illuminate our skies. Occasionally, however, big storms can have a hazardous impact our planet’s atmosphere. In March 1989, an intense solar storm caused a nine-hour blackout across the entire province of Quebec, Canada. The most extreme solar eruption in recorded history occurred in early September 1859. Known today as the Carrington Event after the British astronomer who witnessed the eruptions through his telescope.

The resulting geomagnetic storm disabled telegraph communications worldwide. What’s more, skies “erupted in red, green, and purple auroras so brilliant that newspapers could be read as easily as in daylight,” and as far south as the tropics, according to NASA Science.

Such a massive solar storm today could be far more disruptive because of modern technology, disabling satellite and radio communications, GPS systems, large power grids and the internet. That’s why the National Oceanic and Atmospheric Administration monitors solar conditions through its Space Weather Prediction Center in Boulder, Colorado, and issues forecasts, watches, warnings and alerts.

Northern lights over the Inland Northwest “typically happen a handful of times during the year,” the weather service in Spokane states on its website. They are most likely to be visible from September through March under clear, dark skies with no bright moon.

To lessen the guesswork, the Space Weather Prediction Center recently launched an aurora dashboard online that tells when and where the auroras are most likely to appear.

Nic Loyd is a meteorologist in Washington state. Linda Weiford is a writer in Moscow, Idaho, who’s also a weather geek. Contact: ldweiford@gmail.com.