  On November 3-4 2021, an interplanetary coronal mass injection (ICME) hits
the magnetosphere, sparking a strong G3-class geomagnetic storm and auroras as
far south as California and New Mexico. All detectors of the SEVAN network
registered a Forbush decrease (FD) of 5-10 percentdeep in 1 minute time series
of count rates. We present the results of a comparison of Fd registered on
mountain altitudes on Aragats (Armenia), Lomnicky Stit (Slovakia), Musala
(Bulgaria), and at sea level DESY (Hamburg, Germany), and in Mileshovka,
Czechia. We present as well purity and barometric coefficients of different
coincidences of SEVAN detector layers on Aragats. We demonstrate disturbances
of the near-surface electric (NSEF) and geomagnetic fields at the arrival of
the ICME on Earth.
