Scientists say the earth is being bombarded by high-energy particles unleashed by the strongest solar storm since 2005.
The charged particles are mostly a concern for satellites, which they can disrupt, and astronauts.
But they can also cause communication problems for aircraft travelling near the poles.
The geomagnetic storm has been caused by a potent flare that erupted from the Sun on Sunday.
The NASA Space Weather Prediction Center said on Tuesday it is travelling towards Earth at about 5 million miles per hour.
The effects are likely to be felt on Earth throughout Wednesday. The event is called a coronal mass ejection.
In 1972, a geomagnetic storm provoked by a solar flare knocked out long-distance telephone communication across the state of Illinois, USA.
In 1989, another storm cut power across the Canadian province of Quebec, affecting six million people.