Hanging out on Mount Zion at night can be fun, but no one wants to sit and wait until 3AM for Northern Lights when there is not a realistic possibility of seeing them. Earlier this month, many who read news articles and watched the news found themselves staring at the night sky in disappointment. They had been told there would be perfect conditions for a perfect storm to view the Aurora Borealis, but it was not so.
What goes into a perfect Solar Storm? The solar cycle has a period of about eleven years, which can be quantified by the number of sunspots visible. Solar maximum is characterized by increased solar activity, including coronal mass ejections (CMEs). When the direction of a CME is towards earth, space weather forecasters predict a good chance of seeing the Aurora Borealis, but for the most part, the amount of geomagnetic activity that is yielded is not enough to see the Northern Lights in the United States at all. But sometimes, if in a period of solar maximum and if a large enough CME is headed towards earth with the perfect velocity, low latitude regions could be able to view the Northern Lights. If the cloud cover cooperates and is sufficiently low, we have a perfect storm on our hands.
On Wednesday, January 8, news outlets in the midlatitude states, including Denver, reported that their city would be able to see the Northern Lights that night and the night after. Space weather scientists had observed a large CME capable of producing a large geomagnetic storm in addition to possible aurora in lower latitudes. The media ate it up, along with any citizen who had ever dreamed about seeing the Northern Lights. I found myself among those citizens, and the geo-nerd in me absolutely had to try and see them. I acquired a tripod in hopes of capturing them on camera, started cross-referencing dark sky maps with cloud cover predictions, and had 30 tabs open on my internet browser with articles on how to best see the Lights, how to photograph them, and the current Kp index as reported by SpaceWeather.com.
Kp index measures the level of geomagnetic activity. If the Kp is a 3, latitudes around the poles will only be able to view the aurora such as Alaska, Canada, Greenland, Iceland, Scandinavia, etc. Denver lies at a magnetic latitude such that the Kp index would need to be almost 9, maybe less. Space weather scientists were optimistically hoping for a Kp of 7, which would not ensure the lights be seen in central Colorado, but would offer a possibility of seeing them away from the city light pollution.
Predicting the weather is no simple task, and space weather is no different. Granted, the amount of time that it takes a CME to travel from the sun to the earth is enough to anticipate aurora about a day in advance, but factors such as speed and direction, as well as other factors that space weather scientists do not yet understand make predicting when, where, and if Northern Lights will appear difficult. Aurora chasers frequently make trips to an area with dark sky and wait for hours and hours in the cold of winter without seeing anything.
Residents of the Denver Front Range understood what a rare occurrence seeing the Northern Lights in Colorado is, and the news outlets aptly reported it. However, this incident is a prime example of the disconnect between science and communication to the public, especially once Thursday night rolled around with Golden residents driving up Lookout Mountain in hopes of glimpsing the green curtains of light and only seeing the orange glow of Denver and surrounding suburbs.
The major fail to communicate came Thursday afternoon and evening, when the NOAA Space Weather Prediction Center had posted a report saying the CME was not traveling as fast as they had predicted, and the Kp index for that night would be much less than originally hoped for. Yet the Denver Post[b] and others continued to update their story streams about the possibility of aurora, although it would take a geomagnetic miracle to see them in the United States at all that evening (the Kp got up to a 3).
Viewing conditions were a major factor left out by many articles. Many Denver area residents headed to the suburbs or foothills thinking the sky would be dark enough, but the reality is that light pollution is too much a factor to see them even an hour within the city limits. Also, at this latitude the aurora would appear on the northern part of the sky, so heading to the mountains would have probably blocked the Northern Lights. Aurora occurs in the upper atmosphere, so if the sky is cloudy there will be difficulty viewing them. Thursday night into Friday morning was very cloudy across the United States. Residents who took the short drive up Mount Zion had no chance of seeing any aurora borealis since it was cloudy, too bright from the light pollution of Denver, and the Kp index was so low that even some polar regions did not get any aurora events.
In case of another perfect geomagnetic storm, it would be ideal head north or northeast towards Wyoming to get out of the city limits, depending on cloud cover. Check dark sky maps and cloud cover maps used by astronomers to find an ideal viewing place. Of course, perfect storms rarely happen, and as the solar cycle begins to shift, we will not see solar maximum until about 2024 and will not likely get a chance to see them in Colorado any time soon. It would take a much, much longer drive (or plane ride) up north to get ideal conditions for being able to cross off “See the Northern Lights” from a bucket list.