Look up: Northern lights could be visible across Canada this week

CTV National News: Northern lights show explained Another solar storm has created a new round of northern lights. Paul Hollingsworth on why we're getting so many opportunities to see them.

The northern lights could be visible across most of Canada this week.

A forecast from the U.S. National Oceanic and Atmospheric Administration (NOAA) shows the dazzling display is expected to reach well below the 49th parallel, creating a high likelihood of aurora activity directly overhead throughout much of B.C., Alberta, Saskatchewan, Manitoba, Quebec and the territories. Northern parts of Ontario, Atlantic Canada and the U.S. are also expected to see the lights.

The forecast indicated visibility on Thursday, but further shows are possible through the weekend, some predict.

With clear and dark conditions, and an unobstructed view of the northern horizon, aurorae could also be visible further afield in places like southwestern Ontario and Nova Scotia. According to the NOAA, nearly all of Canada lies within tonight's "view line."

Increased solar activity this week has already led to colourful displays across the country, including in Alberta, Saskatchewan, Ontario and Quebec.

The NOAA classifies the event as four of five geomagnetic storms that could have "severe" impacts on power grids, spacecraft operations and satellite navigation systems.

The powerful solar storm reached Earth at 11:17 a.m. EDT Thursday.

"(The) display will be visible from all of Canada, but for population centres in and east of southern Ontario it will appear towards the northern horizon," Ethen Sun, astronomer at the Dunlap Institute for Astronomy and Astrophysics at the University of Toronto, told CTVNews.ca in an email.

"This is quite rare and only in the years where solar activity is the highest does it happen for a few nights."

Sun says the different colours are due to coronal mass ejections from the sun colliding with different molecules in the atmosphere. A stronger geomagnetic storm causes more high-altitude collisions producing the normal green colours we see, as well as red and even blue aurorae.

"When blended together, just about every colour can be seen as the aurora dances around in the sky," Sun said.

He recommends anyone wanting to witness the northern lights go somewhere with a clear view to the north and to avoid light pollution.

"Keep in mind that because of the high altitude of aurorae, you can be a few hundred kilometres away from the red area (in the NOAA forecast) and still see it," Sun said. "If you live in a downtown area and cannot avoid light pollution, you should be able to see it by taking a photo."

With files from CNN