Geomagnetic storm conditions observed over the weekend strengthened Monday morning, creating a "major disturbance in Earth's magnetic field," the Space Weather Prediction Center said.

The weekend storm is the second in a series of back-to-back storms forecast to hit California every few days up until Christmas, meteorologists said. Snow blankets Mammoth Mountain in California ...

A severe geomagnetic storm could disrupt communications and bring northern lights to parts of California, according to a warning from the National Oceanic and Atmospheric Administration.

Geomagnetic storms could impact the power grid, satellites and GPS technology. "Storm conditions are anticipated to occur overnight as CME progression continues," NOAA said on its website.