Solar Flare Lights Up Alaska Skies

Release Date: 
Wednesday, October 29, 2003


A powerful solar flare that resulted in active aurora displays Tuesday night and Wednesday morning may also trigger outstanding displays on Wednesday evening. “If the skies clear up tonight, it’s going to be a whopping good aurora,” said Charles Deehr, a professor emeritus and aurora forecaster at the University of Alaska Fairbanks Geophysical Institute.
Solar flares are explosions on the sun’s surface that create huge magnetic disturbances when they are pointed toward Earth. On October 28th at 2 a.m. Alaska time, one of the largest solar flares in recent memory sent a shock front ripping toward Earth at 2,500 kilometers per second. The shock, and resulting aurora activity, struck Earth at about 9 p.m. Alaska time October 28th. Where the sky was clear, northerners were able to see brilliant, rippling displays of aurora and curtains of rare red aurora.
Deehr predicts the same effects for the night of Wednesday, October 29, because the solar flare’s shockwave, which reacts with Earth’s magnetic field to produce aurora, is followed by a “magnetic cloud” that will endure in the auroral zone--about 60 miles over our heads--for another night.
“That magnetic cloud takes 24 hours to get past Earth,” Deehr said. Thus far, the large solar flare has emitted protons that have interfered with HF radio communications in the north, but Deehr said the flare has not interfered with electric power grids. 
The chance for seeing tonight’s possible outstanding aurora in the Fairbanks area is best early in the evening, said Rick Thoman, senior forecaster with the National Weather Service in Fairbanks.

“At six or seven p.m. it won’t be too cloudy, but by midnight it’ll probably be too cloudy to see anything,” he said.


An aurora forecast, produced daily by Deehr and others, is available at

Charles Deehr, Professor Emeritus and Aurora Forecaster, UAF Geophysical Institute: 474-7473
Ned Rozell, Science Writer, UAF Geophysical Institute: 474-7468