Lably
Skip to content

1984 Soviet Union tornado outbreak

Tornado outbreak in Ivanovo and Yaroslavl Oblasts, RSFSR

  • 4 min read
  • 2 chapters

Related on Lably

Through Tornado, Russia and Kilogram

Based upon observed damages, the main tornado, an F4 in Ivanovo caused extreme damage, throwing heavy objects of 50,000 kilograms (110,000 lb) for distances up to 200 metres (0.12 mi). Severe thunderstorms also produced hail up to 1 kilogram (2.2 lb) in weight, among the heaviest hailstones confirmed worldwide. In all, the entire tornado outbreak killed at least 69 people (though the exact death toll is unknown) and injured 804. It was previously rated as an F5, however, recent reanalysis has lowered the rating to F4 in 2018 by the European Severe Storms Laboratory.

Meteorological synopsis

On June 8, 1984, a negatively tilted trough caused an extratropical low pressure area to form over the coast of the Socialist Republic of Romania (now non-Communist Romania). Surface moisture moved north from the Black Sea and caused nearby dew points to rise to 20 °C (68 °F); though at that time these were restricted to Romania and the Ukrainian SSR, dew points were higher than average elsewhere. By 1800 UTC, developing thunderstorms over the Ukrainian SSR spread overnight into the Russian SFSR. Between 00 and 12 UTC on June 9, the strengthening low pressure area moved north-northeast over the northwestern Russian SFSR before undergoing occlusion. In the meantime, a strong cold front rapidly advanced along a line extending south from the surface low, then south of Minsk in the Byelorussian SSR (now Belarus), to near Bucharest. This front separated the drier air mass to the north from the warm, moist air mass near the Black Sea, and strong wind speeds near ground level caused vertical mixing. Therefore, dew points actually dropped before the first tornadoes formed, but nevertheless several factors overcame the lower dew points to produce tornadoes. Among these were a strong upper-level jet stream, clear skies causing daytime heating and instability, strong synoptic-scale lifting leading to ascension of updrafts, and high environmental lapse rates promoting thunderstorm development. All these factors combined to produce severe weather near Moscow. The tornadoes occurred in this region because an unstable and moist air mass, supported by warm sea surface temperatures over the Black Sea, had been in place four days before the outbreak began. The unusually strong intensity of the trough in the region on June 8–9, with a 500-millibar geopotential height measured at about 2.7 standard deviations below normal, also favored an intense tornado outbreak.

Sign in to keep reading

One more chapter is free with a Lably account.

More in Earth science