A geomagnetic storm spawned by a giant eruption of gas on the sun reached the Earth's upper atmosphere, interfering with high-frequency airline communications, but causing no major problems, US officials said.
Experts expected the storm to last for up to two weeks. "This is not a super solar storm," said Mr Larry Combs, a space weather forecaster with the National Oceanic and Atmospheric Administration's Space Environment Centre in Boulder, Colorado.
So far, the storm had interfered with airline communications and radio communications for teams on Mount Everest, Mr Combs said. But problems were not widespread.
The storm, called a "coronal mass ejection", is a mass of solar gas that swept toward Earth at two million miles an hour. The usual cycle for such a storm is every 11 years - this one was expected to hit three years ago.
"It is kind of like a snowstorm in June in Colorado," Mr Combs said. Mr Combs said power companies have been notified and were taking precautions to avoid voltage problems and blackouts.
"We will be watching our transmission system very closely 24 hours a day," said Mr Steve Roalstead, spokesman for Xcel Energy, a major Western power provider.
The storm's most visible effect will be the beautiful shimmering light displays, called auroras, that are visible to the naked eye right after dark, said Dale Gary, professor of physics at the New Jersey Institute of Technology.
AFP