Northern Lights Cams in the Northern US

The Kp you need in the lower 48

Because the north magnetic pole is on the Canadian side of the Arctic, the US sees aurora further south than Europe does at the same latitude. Grand Forks at 48°N has about the same geomagnetic latitude as Copenhagen at 56°N. Even so, the border states need a geomagnetic storm:

NOAA’s aurora dashboard draws a “view line”, the southern edge of where aurora may be seen low on the horizon for the next half hour. If your town is near that line, face north and use a phone camera: it will often show colour, especially the high red glow of a big storm, before your eyes can.

The cameras

• Mt. Katahdin looks north from Millinocket Lake in northern Maine with a low-light Sony camera. Katahdin Woods and Waters National Monument next door is an International Dark Sky Sanctuary, and the sky here is among the darkest in the eastern US.
• Sebec Lake is the same operator’s second Maine sky camera, pointed north-north-east over the lake with an 80° view.
• UND skycam is the University of North Dakota’s atmospheric-sciences camera on the Grand Forks campus. It faces west over the flat Red River valley, so it shows the sky rather than the northern horizon: it catches big storms, when aurora spreads overhead.
• St. Mary, Glacier National Park is the Park Service’s camera on the east side of the park, a snapshot that refreshes every few minutes. Waterton-Glacier is an International Dark Sky Park, and St. Mary Lake is one of Montana’s best-known aurora spots.

Storm nights: what actually happens

A US aurora night usually starts with a coronal mass ejection forecast to arrive within a day or two. NOAA issues a geomagnetic storm watch, which is what turns on the storm banner at the top of this page. Arrival times are uncertain by several hours, and the storm’s strength depends on the direction of its magnetic field, which is only measured about an hour before it reaches Earth. So the useful habit is to check after dark and keep checking: the best displays in the lower 48 often come in a burst of 20–40 minutes, sometimes before midnight and sometimes in the small hours.

Unlike the Arctic, the northern US has real darkness all year, so a storm in June can be seen, if only for a few hours around midnight. The equinox months of March and September to October are statistically the most active.

Where to go when a storm is forecast

Get a clear view to the north, away from towns. Good choices: Voyageurs National Park and the Boundary Waters in northern Minnesota, both certified dark-sky places; the Lake Superior shore of the Upper Peninsula, and the Headlands International Dark Sky Park at Mackinaw City at the tip of the Lower Peninsula; the open prairie of North Dakota anywhere north of I-94; Glacier National Park’s east side in Montana; and in Maine the Katahdin region or the Down East coast. Lake-effect cloud off the Great Lakes is the main spoiler from November to February, while the northern Plains often clear sharply behind a cold front.

For alerts, NOAA’s Space Weather Prediction Center sends free email notices of storm watches and warnings, and the camera ranking above tells you which of these skies is dark and clear at that moment.