A violent supercell storm produced severe hailstorm over central Slovenia on Wednesday evening, July 29, 2020. Ice stones up to 10 cm (4 inches) in diameter left enormous damage along its path in what is now the first giant hailstorm event of 2020 in Europe.
A large upper wave was moving across northern Europe, while an associated diffuse cold front was extending towards the Alps. Moderate westerly winds over Slovenia created a moderate wind shear, generating environmental conditions that were conducive to support such severe storm.
"The low-level conditions revealed a classic moisture pooling (moisture advection) with the easterly flow towards the Dynaric mountain range," Severe Weather Europe (SWE) meteorologists explained.
"Near-surface conditions were ever more robust in central Slovenia, therefore even higher instability was likely present."
The storm began over the mountainous terrain in the higher Alps, eventually spreading towards southeast across southern Austria and the border with Slovenia.
Video of severe roof damage after a hailstorm in Rodica near Domžale, Slovenia last night, July 29th. Thanks to Nastja Volf for the report - posted with permission. pic.twitter.com/ZPenfG6wue— severe-weather.EU (@severeweatherEU) July 30, 2020
The main storm was marked near Vodice, where the violent weather started dropping hailstones up to 8 cm (3 inches) in the town.
"The storm evolution was extremely explosive! The view into the developing towers from a distance was beyond spectacular," SWE wrote.
It moved slowly to the east towards Domzale, where up to 10 cm (4 inches) of hail fell. More hail was reported in some swaths of central Slovenia in the late evening but was less intense than earlier.
The cluster also generated numerous red sprites or large-scale electrical discharges that take place high above thunderstorm clouds.
Massive damage was reported from Vodice to Domzale and further southeast. Many cars and roofs were hit, but no one was injured.
Photos and videos shared by citizens on social media show shattered windows of cars and torn roofs.
According to SWE, this was the biggest hail event in Europe this year.
Severe damage after a hailstorm in Rodica near Domžale, Slovenia last night, July 29th. Thanks to Nastja Volf for the report - posted with permission. pic.twitter.com/RPH56bYdow— severe-weather.EU (@severeweatherEU) July 30, 2020
Featured image credit: Nastja Volf