STEVE (Strong Thermal Emission Velocity Enhancement) is a beam of light visible in northern altitudes made up of a jet of hot atmosphereic plasma and, thoug hard to spot with the naked eye, is readily captured using photographic methods, according to LSM's resident stargazer and weatherman Toms Bricis, who presents more pictures of STEVE in the video below.
Though it looks in some ways similar to the Aurora Borealis or Northern Lights, STEVE is quite a different phenomenon and you can read more about it/him at this astronomical website.
STEVE has been captured this week by photogrpahers in both Latvia and Estonia.