The next time the Sun launches an especially powerful blast of charged particles toward Earth, the northern Great Lakes could be in trouble. When the blast hits us, the ground and Earth’s magnetic field could conspire to knock out power grids — perhaps triggering blackouts that could last for weeks or longer.

The Sun periodically belches out giant clouds of charged particles. Most of them move away from Earth. And most of the ones that hit us don’t cause major problems.

But the most powerful can cause big headaches. Earth’s magnetic field funnels the charged particles toward the surface, where they can knock out communications and power systems. In 1989, for example, a storm caused a blackout across a large part of Canada.

Studies have suggested that the most powerful storms could leave some regions without power for weeks or months, and cause a trillion dollars in economic losses.

A recent study mapped some of the risk from once-in-a-century storms across parts of the United States. It looked at how the ground conducts electricity, and at how much of a solar storm’s activity is likely to hit a given region.

The study found that northern Minnesota faces the greatest risk, with the surrounding Great Lakes region also with a higher chance of problems.

The study left about half of the U.S. unmapped, though — especially the heavily populated Northeast. So more work needs to be done to assess the risks of a major solar barrage.

Script by Damond Benningfield