A high-speed solar wind stream hit Earth's magnetic field last night, sparking a geomagnetic storm (Kp=5-6) that lasted more than 15 hours. Northern Lights spilled across the Canadian border and were spotted in several US states. Joseph Shaw sends this picture from Bozeman, Montana:

Image
© Joseph Shaw
"The red auroras were just visible to the naked eye and easily captured by my Nikon D300," says Shaw. "Excellent treat!"

NOAA forecasters estimate a 45% chance of continued geomagnetic activity over the next 24 hours. High-latitute sky watchers should remain alert for auroras.

.