Encyclopedia
Tornado
Tornado: A strong small-scale atmospheric vortex with a diameter up to 1000 m, in which air rotates at speeds up to 100 m/s, possessing significant destructive power
Source: "EMERGENCY SAFETY. NATURAL EMERGENCIES. TERMS AND DEFINITIONS. GOST 22.0.03-97/GOST R 22.0.03-95"
(approved by the Decree of the Russian State Standard dated 25.05.1995 No. 267)