Eyes up! The Northern Lights may shine bright across Canada in the nights ahead
Displays of the Northern Lights this close to the March Equinox sometimes explode with light and colour!
Eyes to the sky! A passing solar storm may spark bright auroras across Canada later this week.
On the morning of Monday, March 16, a moderate-strength solar flare exploded on the Earth-facing side of the Sun. In the aftermath, satellite images captured the eruption caused by the flare, as it expanded away from the Sun.
That eruption, known as a coronal mass ejection, is now travelling towards Earth, and should arrive sometime overnight Wednesday into Thursday.
The M2.7 flare from March 16, 2026 (left), as imaged by the Solar Dynamics Observatory, and NASA's ENLIL computer model run showing the arrival of the solar storm at around 12 UTC on March 19. (NASA)
When this 'solar storm' reaches us, it will likely result in a disturbance to Earth's magnetic field, known as a geomagnetic storm.
Forecasters with NOAA's Space Weather Prediction Center have issued a G2 (moderate) geomagnetic storm watch for the early hours of Thursday, March 19, in anticipation of the solar storm's arrival.
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The SWPC forecast specifically calls for G1 (minor) storm levels to begin around 11 p.m. Wednesday night, through until 2 a.m. Thursday morning, EDT. Following that, G2 (moderate) levels are forecast to occur from 2 a.m. through 8 a.m. EDT.
That favours central and western regions of Canada for the strongest aurora displays.
However, forecasters say the timing is still uncertain for this event.
The CME could arrive sooner, sparking brighter auroras earlier on Wednesday night, and thus focused more on eastern regions of the country.
It is also possible that it could reach us later, with the brightest auroras then occurring during the day on Thursday, causing us to miss the show.
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Are there clear skies?
As of Tuesday afternoon's weather forecast, sky conditions are not the most favourable for this event.
In the eastern half of the country, Northwestern Ontario, as well as a band of sky across eastern New Brunswick, Prince Edward Island, and the western half of mainland Nova Scotia appear to be clear that morning.
In the west, southern Manitoba, southwestern Saskatchewan, southern Alberta, and the interior and central regions of British Columbia appear to have the best chance of clear skies.
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Equinox Cracks?
The Sun and Earth are each surrounded by their own magnetic field. The Sun's magnetic field contributes to solar activity, such as solar flares and coronal mass ejections (aka solar storms). Meanwhile, the Earth's magnetic field reacts to these solar storms, and to the flow of the solar wind, which results in coloured displays across Canadian skies known as the Aurora Borealis, or the Northern Lights.
Auroras appear around the north and south poles of Earth as Earth's geomagnetic field traps particles from the solar wind and funnels them down into the atmosphere. (NASA)
Due to Earth's tilt, our planet's magnetic field is nearly always out of alignment with the Sun's magnetic field. So, even under the absolute ideal conditions for a solar storm or the solar wind to result in auroras, that misalignment effectively reduces the overall intensity of any that do appear.
However, around the spring and fall equinoxes, the magnetic fields of the Sun and Earth line up better than they do during the rest of the year. This can cause strong connections to form between the two, effectively opening up 'cracks' in Earth's magnetic field.
The orientation of Earth's magnetic field at northern summer solstice (left), equinox (centre), and northern winter solstice (right). The Sun is located far off the left side of the field of view, and its magnetic field is oriented most in alignment with the centre panel. (NASA/Scott Sutherland)
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This is known as the "Russell-McPherron effect" and it produces fast-tracks for particles from the solar wind or from solar storms to stream down through that protective barrier and into the upper atmosphere.
As a result of all this, auroras that occur around the equinoxes can be some of the brightest and most colourful of the entire year!
This colourful aurora display was captured by Tree and Dar Tanner from central Alberta, on March 23, 2023. (TeamTanner)
Given that the geomagnetic field is effectively invisible, it is difficult to factor these 'equinox cracks' into any space weather forecast. Thus, they are not taken into account with what NOAA's forecasters expect from this CME arrival.
We will need to wait until it reaches us, sometime Wednesday night or Thursday, to see what happens.
Check back for updates on the weather and aurora forecast, as they come in.