1883day.year

An F5 tornado strikes Rochester, Minnesota, leading to the creation of the Mayo Clinic.

In 1883, an F5 tornado devastated Rochester, Minnesota, leading to the founding of the world-renowned Mayo Clinic.
On August 21, 1883, a powerful F5 tornado tore through Rochester, destroying much of the city and causing over 30 fatalities. The disaster overwhelmed local medical facilities, prompting community leaders to seek assistance. Dr. William Worrall Mayo and his sons, William James Mayo and Charles Horace Mayo, collaborated with the Sisters of Saint Francis to treat the injured. Their efforts highlighted the need for a dedicated hospital equipped to handle large-scale emergencies. Supported by local fundraising, Saint Marys Hospital opened in 1889 and evolved into the Mayo Clinic. Today, the Mayo Clinic is a global leader in medical research, education, and patient care, with its origins rooted in the response to this tragic tornado.
1883 An F5 tornado Rochester, Minnesota Mayo Clinic
1945day.year

Physicist Harry Daghlian is fatally irradiated in a criticality accident during an experiment with the Demon core at Los Alamos National Laboratory.

Harry Daghlian suffered a fatal radiation accident during a criticality experiment with the Demon core at Los Alamos in 1945.
Physicist Harry Daghlian was conducting a plutonium criticality experiment on the Demon core at Los Alamos National Laboratory. On August 21, 1945, a lapse in protocol caused a reflector brick to slip, triggering an uncontrolled neutron chain reaction. Daghlian received a massive dose of radiation while attempting to halt the reaction and collapsed soon after. He endured severe radiation burns and died 25 days later, becoming the first casualty of a criticality accident. The incident led to the implementation of stricter safety procedures and remote-handling techniques. Daghlian's sacrifice highlighted the grave risks inherent in early nuclear research and shaped laboratory protocols worldwide.
1945 Harry Daghlian criticality accident Demon core Los Alamos National Laboratory
1986day.year

Carbon dioxide gas erupts from volcanic Lake Nyos in Cameroon, killing up to 1,800 people within a 20-kilometre (12 mi) range.

A sudden carbon dioxide gas eruption from Lake Nyos in Cameroon kills up to 1,800 people.
On the night of August 21, 1986, a massive release of carbon dioxide from Lake Nyos descended upon nearby villages in Cameroon. The dense gas hugged the ground, suffocating people and livestock without warning. Estimates of the death toll range up to 1,800 within a 20-kilometre radius of the lake. Scientists later identified a limnic eruption as the cause, a rare phenomenon where dissolved gas violently erupts from deep lake waters. The disaster prompted international research into preventing similar events at volcanic lakes. Lake Nyos remains monitored to mitigate future gas buildups and protect local communities.
1986 volcanic Lake Nyos Cameroon
1988day.year

The 6.9 Mw Nepal earthquake shakes the Nepal–India border with a maximum Mercalli intensity of VIII (Severe), leaving 709–1,450 people killed and thousands injured.

A magnitude 6.9 earthquake strikes the Nepal–India border, causing extensive damage and hundreds of fatalities.
On August 21, 1988, a powerful earthquake of magnitude 6.9 struck near the Nepal–India border. The tremor registered a maximum Mercalli intensity of VIII, classified as severe. The quake destroyed homes, roads, and infrastructure across the region. Casualties numbered between 709 and 1,450 people, with thousands more injured. Remote mountain villages were particularly hard hit, complicating rescue and relief efforts. The disaster led to improved seismic monitoring and building codes in Nepal and northern India.
1988 Nepal earthquake Mercalli intensity
1994day.year

Royal Air Maroc Flight 630 crashes in Douar Izounine, Morocco, killing all 44 people on board.

Royal Air Maroc Flight 630 crashes near Douar Izounine, Morocco, killing all 44 on board.
On August 21, 1994, Royal Air Maroc Flight 630 crashed shortly after takeoff from Agadir–Al Massira Airport. The aircraft went down in the Douar Izounine area, killing all 44 passengers and crew. Initial investigations pointed to a possible in-flight emergency, though final conclusions remained unclear. The accident prompted reviews of safety procedures within the airline and Moroccan aviation authorities. Families of the victims demanded answers about the causes and accountability. This tragedy remains one of Morocco's deadliest aviation accidents to date.
1994 Royal Air Maroc Flight 630 Morocco
1995day.year

Atlantic Southeast Airlines Flight 529, an Embraer EMB 120 Brasilia, attempts to divert to West Georgia Regional Airport after the left engine fails, but the aircraft crashes in Carroll County near Carrollton, Georgia, killing nine of the 29 people on board.

Atlantic Southeast Airlines Flight 529 crashes near Carrollton, Georgia, after an engine failure, resulting in nine fatalities.
On August 21, 1995, Atlantic Southeast Airlines Flight 529 suffered a catastrophic left engine failure shortly after departing from Hartsfield-Jackson Atlanta International Airport. The crew attempted to divert to West Georgia Regional Airport, but the aircraft crashed in Carroll County near Carrollton, Georgia. Nine of the 29 people on board lost their lives, while the remainder survived with varying injuries. Investigators determined a cracked turbine engine blade as the root cause. The accident led to enhanced inspection protocols for regional airline engines. Flight 529 remains a case study in emergency response and mechanical integrity in aviation safety.
1995 Atlantic Southeast Airlines Flight 529 Embraer EMB 120 Brasilia West Georgia Regional Airport Carroll County Carrollton, Georgia