The maximum of the Leonid activity in 2017 is expected during the night of the 17th November 2017. The Leonids are a prolific meteor shower. It tends to peak around November 17, but some are spread through several days on either side and the specific peak changing every year.
Conversely, young trails are spatially very dense and the cause of meteor storms when the Earth enters one. Usual counts during a storm exceed 1000 meteors per hour, to be compared to the annual background (1 to 2 meteors per hour) and the shower background (a few per hour).
A meteor shower is a celestial event in which a number of meteors are observed to radiate from one point in the night sky. These meteors are caused by streams of cosmic debris called meteoroids entering Earth's atmosphere at extremely high speeds on parallel trajectories. Most meteors are smaller than a grain of sand, so almost all of them disintegrate and never hit the Earth's surface. (From: Wikipedia, license: CCA-SA)