A powerful burst of sunshine is expected to boost the Northern Lights Thursday evening, potentially bringing colorful sky shows to southern Alabama and Northern California.

The National Oceanic and Atmospheric Administration’s Space Weather Prediction Center said Thursday that plasma and other materials from the Sun reached Earth at 11:17 a.m. ET, triggering what the agency called a “severe” geomagnetic storm.

These types of solar storms occur when solar eruptions known as coronal mass ejections hurl giant clouds of plasma into space. When aimed at Earth, the plumes of charged particles collide with the planet’s magnetic field, interacting with atoms and molecules in the upper atmosphere, creating radiant auroras.

When conditions are clear, skygazers in Canada and many northern US states – including Alaska, Washington State, Idaho, Montana, North Dakota, Michigan, Minnesota and Wisconsin – will likely have the best views of the Northern Lights. Very active auroras may also be visible in parts of Northern California, Nevada, Oklahoma, Alabama, Ohio, Pennsylvania and New York.

This week’s solar storm is the strongest since May 10, when the Space Weather Prediction Center observed an even stronger and much rarer solar storm. Before the May event, NOAA had not issued a severe geomagnetic storm watch since 2005.