  We explore the anomalous behavior of the equatorial quasi-biennial
oscillation (QBO) in zonal wind which it exhibited, since February 2016. In
more detail, QBO interrupted its regular pattern and the eastward stratospheric
winds unexpectedly reversed to a westward direction. We focus on the temporal
evolution of the equatorial zonal wind in the altitude region 70 - 10 hPa,
investigating particularly whether this unprecedented event could be considered
as a result of scaling effect in the equatorial zonal wind. Furthermore, the
link between the QBO abnormal behaviour in 2016 with the strong El Ni\~no event
is investigated.
