It had been a day of brutal summer heat. By noon, towering cumulonimbus clouds were building and drifting toward San Justo, fed by heavy humidity and an atmosphere wound dangerously tight. Around one o'clock the first scattered rain fell — the kind of uneasy, isolated shower that locals would later recognize as a warning they had no way to read. There were no sirens, no radar alerts, no warning system of any kind for an event the region had never seen at this scale. People went about their afternoon in the wet heat, unaware that the sky overhead was assembling something monstrous.

At about 2:15 in the afternoon the tornado dropped into an open field outside town. It moved slowly, almost deliberately, tracking to the south-southwest. It hurled cattle more than 30 meters into the air, snapped power poles, flattened outbuildings, and sucked a lagoon dry. Then it crossed the General Belgrano railway tracks and entered San Justo. At its widest it spanned some 300 meters — a grinding wall nearly a third of a kilometer across. It reached F5 intensity, the top of the Fujita scale, then abruptly weakened and dissipated barely seven minutes after touching that peak. In those minutes it had cut a path of total destruction through the western part of town.

What people remember most, beyond the noise, is the color. Tornadoes rarely change hue, but locals are nearly unanimous that this one did — opening as a deep violet, then turning red as it tore into the brick homes and carried their pulverized dust skyward. It is an eerie detail, and a telling one: the red was the town itself, ground to powder and lofted into the funnel. The greatest danger, though, came from wood. The tornado shattered countless wooden planks and beams and flung them outward as spears. It was these projectiles, more than the wind alone, that killed most of the sixty-three who died — ordinary lumber turned lethal in seconds.

When the funnel lifted, the supercell behind it kept hammering San Justo with violent rain for another hour before rescuers could begin. The scenes that followed are almost unbearable in their plainness. The local hospital filled past capacity and was turned into a morgue, bodies laid out and waiting to be claimed. Many of the dead were caked in mud or so badly injured that families could not recognize their own. These were not statistics. They were neighbors, children, parents — people who had been alive and ordinary an hour before, going about a hot summer afternoon in a town where nothing like this had ever happened or would happen again.

San Justo has never let the day be forgotten. In 2013, on the fortieth anniversary, a memorial was raised near the corner of Roque Sáenz Peña boulevard and 1° de Mayo street, dedicated to those who perished and to the relatives left behind. In 2018, a group of sanjustinos made a documentary, "Vorágine" — Whirlwind — following three relatives of the dead as they returned to that afternoon. Directed by Fernando Molinas and produced by Imanol Sánchez, it is less about meteorology than about grief that does not expire. In 2017, the tornado finally received its official F5 rating, confirming what the town had always known: it had survived the worst storm the hemisphere has ever recorded.