By emitting radar waves the radar registers how precipitation moves . It will then receive echoes if the waves hit precipitation particles. The animation shows precipitation during the last hours, the last picture in the sequence being the most recent. The time at which it was taken is given (in local time) in the upper right corner.

Under certain conditions the radar waves are deflected and hit the ground instead, giving false echoes. False echoes can be recognised by being fairly motionless.