Following the traditional way of expression. geomagnetic storms have been classified into three types; flare-type Sc storms. CH-type Sg storms. and DB-type Sc storms (Sc:sudden commencement;CH:coronal hole;g:gradual;DB:disparition brusque). https://www.hindigyanvishv.com/mega-pick-Shrimps-Is-Bugs-Mug-special-find/