A question we commonly receive is “When is the best time to see the northern lights?”. While we can maximize our odds, there really is no way to predict the Northern Lights or nature for that matter. Because of our understanding through scientific observation we are now capable of forecasting nature to a degree. Like storms here on earth, the Northern Lights do not really run like clockwork, but there is a natural rhythm to their presence. In order to give you some insight on what to consider when forecasting the Northern Lights, I have compiled some scientific information. This will better explain the conditions you need to see the Aurora Borealis.
Let’s start with space. From the sun, there is constant solar wind that flows throughout the galaxy reaching everything in orbit. When the sun’s activity intensifies due to solar flares (explosions on the sun’s surface) or from enormous explosions on the sun’s surface known as mass coronal ejections, the sun thrusts charged particles into space. These particles are then picked up by the solar wind and carried rapidly to earth where they interact with the earth’s magnetic fields located in the upper atmosphere.
When this cataclysmic event occurs, the Northern Lights appear. During the eleven-year solar cycle there is an increasing progression of solar storms and coronal mass ejections that builds to a peak. The solar cycle has been at its peak since 2013 and will continue through 2015.
FAST FACT: At the peak of the cycle, several solar flares may occur each day, with an average lifetime of 10 minutes.
In 1859, the sun ejected such a large burst of charged plasma (most likely a coronal mass ejection) that reached the earth. This ejection was so strong, that when the particles collided with our atmosphere, many telegraphs were fried. This solar event, which became know as the Carrington Event (named after one of the English astronomers who observed it), was so huge that the accounts say the Northern Lights were seen as far as Cuba.
When intense space weather happens such as this, the magnetic force from the Earth’s Northern and Southern poles pulls the solar wind and all it contains towards earth—gravity does the rest. Seeing solar activity far away from the North Pole, such as the Carrington Event of 1859, is very rare. Your best chance to see solar activity colliding with earth is to travel to the eye of the geomagnetic storm—either the North Pole or the South Pole.
FAST FACT: Telegraphs in Philadelphia were spitting out “fantastical and unreadable messages,” one paper reported, with some systems unusable for hours after the Carrington Event in 1859.
Now that we understand the space weather conditions for the Auroras to occur, let’s look at the ideal climatic conditions for observations here on earth. In order to see the photoactivity of the Northern Lights, you need to be on the lookout when it is dark… really dark. However, there are certain times during the night that are typically better for Northern Lights viewing that depend on the earth’s rotation. Auroral ovals are the specific areas, in ring form, over the two poles where solar winds interact with the earth’s magnetic force. The ovals stay in place while the Earth rotates under them. These ovals are called ovals for a reason—they are not perfectly circular. So, where you are on the earth makes a significant difference for seeing the Northern Lights and the time is a significant factor as well. The northern oval’s band widens and dips farthest south around midnight, making that the most ideal time for viewing. The oval stays in this position until 3 a.m. local time.
Accounts of the Carrington event and the cave paintings found in southern france that depict the aurora amaze me. Solar activity of that caliber, most likely an enormous coronal mass ejection, is the only explanation for the Northern Lights to reach places that far south. However, as I mentioned in a post filled with facts about the Northern Lights, light pollution, or lack thereof, also plays a significant role. When on the lookout for the Northern Lights you want few illuminated distractions. The farther away you are from man-made light sources the better your chances are for seeing the Northern Lights.
FAST FACT: According to many universities including the University of Hong Kong, Hong Kong’s light pollution is the worst in the world. If you want to stargaze, scratch this place off your list.
The last element for a perfect viewing of the Northern Lights is the local weather. Auroras happen at high altitudes in the earth’s upper atmosphere and in the case of a thick cloud cover in a lower atmosphere, there’s not much to see on the ground.
On my first trip to Alaska I constantly updated myself on all of the forecasting systems to guarantee I saw the Northern Lights, yet I still missed out, sleeping while others chanceds upon them. From that experience I learned that I cannot just depend on scientific knowledge and technology. You could be inside next to a cozy fire or in your comfortable warm bed when the Northern Lights appear out of nowhere. In an older post, Good Odds: Looking for the Northern Lights, I told the story about the group on a night-time reindeer walk who were surprised by an unexpected light show. That is why whenever I go to Alaska on a Gondwana Ecotours trip, I am actively scouting for the Northern Lights every night. As soon as I see them dance across the sky I run inside the lodge and tell my fellow travelers to wake up and come outside to experience the world’s best light show.