We may be due for the consequences of an intense solar storm passing over the Earth tomorrow after what NASA is calling a "significant" solar flare burst from the Sun yesterday afternoon.

According to NASA, the flare is a X1.6 class, where X-class solar flares are the most intense of solar flares, and 1.6 denotes that this specific flare is somewhere between the "small" and "medium" of this class. An X3 flare, for instance, would be three times as intense as an X1 class solar flare, and an X1 flare would be significantly stronger than any M-class flare - the stage of flare known to cause small to medium radio blackouts and moderate radiation storms.

"Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground," NASA reported. " However - when intense enough - they can disturb the atmosphere in the layer where GPS and communications signals travel."

In the case of this flare, the NOAA expects it to be followed by moderate geomagnetic storms as early as tomorrow, as the consequence of two coronial mass ejections (CME) associated with the flare. (Scroll to read on...)

[Credit: NASA/SDO/Goddard]

Now "a G3 (Strong) Geomagnetic Storm Watch has been issued for September 13th due to the combined influence of these two events with G1 (Minor) storming anticipated to continue into September 14th," as reported by the NOAA.

Geomagnetic storms occur when solar wind presses on Earth's magnetosphere. Not only can this cause auroras as far as over North America, but it can also disrupt magnetic navigation and even energize ground induced currents (GICs) - which can disrupt power distribution through underground cables.

Bob Berman, an astronomer manning the Slooh Space Telescope, told Business Insider that that is what solar experts fear most.

"A government-sponsored panel in 2008 estimated that [a severe GIC] event today would likely destroy the US electrical grid, inflict a staggering $1 to $2 trillion dollars worth of damage, and require over a year to repair," he explained. "So it's more than of mere academic interest to monitor and observe these violent events as they unfold. Plus, they're amazing to watch."

According to the NOAA, aurora watchers in the northern US should start looking for activity on Thursday and Friday night. They might get a pretty spectacular show, especially if all the lights suddenly go out.