Unusual Twilights Over Western Europe
October 21, 2008
Provided and copyright by: Peter Krämer
Summary Author: Peter Krämer
A series of incredibly bright morning and evening twilights could be seen during mid February of 2008 over western and northern Europe. Strange twilight colors were reported from the United Kingdom, Scandinavia, The Netherlands, and Germany. This bizarre display started a few minutes after sunset with an eerie yellow light in the western skies that was bright enough to illuminate the landscape. After about 10 minutes, the yellow light became surrounded by a kind of brownish arc, turning into purple, as the yellow glow slowly faded and took on a reddish hue. There was also a faint brownish-red shimmer in the east, reaching up to about 10 degrees above the horizon.
These lights were visible up until about an hour after sunset. Some observers reported similar effects at dawn beginning with the red light and ending with the yellow glow. In some areas, cirrus clouds appeared as dark shadows in front of the light, indicating that the source of the light was perhaps the stratosphere. The photograph above was taken from Bochum, Germany on February 19 at 6:13 pm local time, about 20 minutes after sunset. The strange twilight effects were possibly caused by polar stratospheric clouds (PSC), which are a variation of nacreous clouds, PSCs form in altitudes of about 14 miles (20 km) or more, and require temperatures of at least -108 F (-78 C). On February 18, 2008 extremely cold air was in place in the stratosphere over The Netherlands. It’s not known when these clouds were last observed (if ever) this far south before.