Gargantuan Hail in Argentina

Abstract

On 8 February 2018, a supercell storm produced gargantuan (> 15 cm or > 6 inches in maximum dimension) hail as it moved over the heavily populated city of Villa Carlos Paz in Córdoba Province, Argentina, South America. Observations of gargantuan hail are quite rare, but the large population density here yielded numerous witnesses and social media pictures and videos from this event that document multiple large hailstones. The storm was also sampled by the newly installed operational polarimetric C-band radar in Córdoba. During the RELAMPAGO campaign, the authors interviewed local residents about their accounts of the storm, and uncovered additional social media video and photographs revealing extremely large hail at multiple locations in town. This article documents the case, including the meteorological conditions supporting the storm (with the aid of a high-resolution WRF simulation), the storm’s observed radar signatures, and three noteworthy hailstones observed by residents. These hailstones include a freezer-preserved 4:48-inch (11:38-cm) maximum dimension stone that was scanned with a 3D infrared laser scanner, a 7:1-inch (18-cm) maximum dimension stone, and a hailstone photogrammetrically estimated to be between 7:4 and 9:3 inches (18:8-23:7- cm) in maximum dimension, which is close to or exceeds the world record for maximum dimension. Such a well-observed case is an important step forward in understanding environments and storms that produce gargantuan hail, and ultimately how to anticipate and detect such extreme events. (Capsule Summary) Gargantuan hail fell in Argentina on 8 February 2018, including one hailstone that is possibly a world-record for maximum dimension. We document eyewitness and social media accounts of the hail, and analyze the parent storm and its environment.

A Hail Growth Trajectory Model for Exploring the Environmental Controls on Hail Size: Model Physics and Idealized Tests

“…Some previous studies have ignored it entirely (e.g., ASZ16), citing low raindrop concentrations and thus unlikely collisions with hailstones. However, portions of the updrafts of deep convective storms are known to contain raindrops, often observed with dual-polarization radar as differential reflectivity (Z DR ) columns (see Kumjian et al 2014, and references therein) and specific differential phase (K DP ) columns (van Lier-Walqui et al 2016). Unlike low-inertia cloud droplets, raindrops have significant inertia and thus are unlikely to follow streamlines around hailstones.…”

“…Second, the hailstone only ascends ;2.5 km before falling out of the storm; in other words, large or repeated up/down vertical excursions are not observed in these trajectory calculations. Third, the final fallout of the hailstone is on the left (relative to storm motion) side of the low-level mesocyclone, a typical place where large hail is observed in supercells (e.g., Browning 1964;Browning and Foote 1976;Kumjian and Ryzhkov 2008).…”

“…Using reanalysis data, Rädler et al (2018) built a simple statistical model based on instability and deep-layer shear to predict the occurrence of severe hazards, including hail, that was able to reasonably reproduce observed hail climatological features in Europe. In addition, the community is only beginning to recognize different ''flavors'' of hail threats and to identify their distinguishing features on radar displays or from environmental cues, including storms that produce large amounts of small hail (e.g., Kalina et al 2016;Wallace et al 2018;Kumjian et al 2019;Friedrich et al 2019) or those that produce giant or gargantuan hail (Blair et al 2011;Gutierrez and Kumjian 2018;Kumjian et al 2020). Conceptual models for why or how these storms produce these distinct types of hail threats do not exist.…”

To be or not to be, that is the question: The Marsala meteorite (Italy, 1834) and the role of the doubtful meteorites in the history of meteoritics

“…In this regard, Kumjian et al. (2020) described a thunderstorm (Argentina, 2018) that produced some of the biggest hailstones on record (ca. 18.8–23.7 cm wide).…”

Utilizing a Storm-Generating Hotspot to Study Convective Cloud Transitions: The CACTI Experiment

“…The wide range of environmental conditions in central Argentina and the high frequency of orographic convective clouds that evolve into deeper congestus, initiate into deep convection Houze 2011, 2016;Mulholland et al 2018), and organize into mesoscale systems near the SDC range (Anabor et al 2008;Romatschke and Houze 2010;Rasmussen et al 2014Rasmussen et al , 2016 make it an ideal location to quantify interactions between convective clouds and their surrounding environment. Extreme storms in Argentina stand out as being some of the world's deepest (Zipser et al 2006), largest (Velasco and Fritsch 1987), and longest-lived with some of the highest lightning flash rates (Cecil et al 2015) and largest hail (Cecil and Blankenship 2012;Kumjian et al 2020) on Earth. The convective lifecycle in this region is significantly influenced by orographic flows (Nicolini and Skabar 2011;Rasmussen and Houze 2011;Bueno Repinaldo et al 2015;Mulholland et al 2019Mulholland et al , 2020, the South American low level jet (Nicolini et al 2002;Salio et al 2002Salio et al , 2007Saulo et al 2004Saulo et al , 2007Borque et al 2010), and synoptic-scale troughs that induce the Northwestern Argentinean ("Chaco") Low (Seluchi et al 2003), free tropospheric subsidence (Ribeiro and Accepted for publication in Bulletin of the American Meteorological ociety.…”