WASHINGTON - A severe geomagnetic storm caused by two significant solar eruptions reached Earth Tuesday, sparking concerns about power disruptions, US forecasters said.

The storm, which began at around 10:00 am EDT (1400 GMT), ranked as a G4 geomagnetic storm on the National Oceanic and Atmospheric Administration (NOAA) scale of one to five, said Thomas Berger, director of the US Space Weather Prediction Center, which is part of the NOAA.

"This is one of two severe geomagnetic storms that we have experienced during this current solar cycle," Berger said during a teleconference.

Officials with the center said that the last G4 storm was recorded in 2013 and that it has been about a decade since a G5 storm, the strongest, hit our planet.

The storm was caused by a pair of coronal mass ejections observed leaving the Sun on Sunday, which later combined into one eruption and arrived 14 or 15 hours earlier than expected, Berger said.

However, the storm, which should last 24 to 36 hours, was not directly pointed at Earth, but just a "glancing blow," he said.

So far, no damage has been reported, but the center said it's possible that it could disrupt satellite navigation systems and create harmful geomagnetic induced currents in the power grid and pipelines. Meanwhile, Northern lights may be seen as low as Pennsylvania to Iowa to Oregon.