A heat wave is characterized by a marked and sustained increase in temperatures, especially the maximum, occurring in several cities above what is considered extreme.
As of December 11, a marked increase in temperatures began to be registered, especially the maximums in a vast area of the central and northern Patagonian region, affecting the south of Córdoba, the south of Santa Fe, the south of Entre Ríos, a large part from the province of Buenos Aires, La Pampa, east of Mendoza, east of Neuquén and Río Negro.
As of the 19th, this anomalous situation began to expand towards the north of Argentina and intensified again over the central part, affecting 18 provinces, giving way to the same around December 30 in the central part and between the 1st and 2nd January in the extreme north of the country with the passage of a cold front that produced a change in air mass.
As a result, most of the localities located between 30ºS and 40ºS registered 1 or 2 heat waves in the period, with durations of between 5 and 18 consecutive days, and average minimum temperatures above 4 °C and average maximum higher than 6 °C compared to normal for the time.
The long persistence of this heat wave (22 days) made the event exceptional, breaking several records in terms of the largest number of consecutive days with minimum and maximum temperatures above the average in several weather stations in the affected zone.
It was the first heat wave whose level of danger to health was categorized as extreme (red alert). The National Meteorological Service and the Ministry of Health warned the population of the cities and surroundings of Buenos Aires and Rosario about the risks to be avoided and the basic care to be followed by the population in the event of intense heat. It occurs in exceptional cases of heat waves, in which it can affect all healthy people, and not just risk groups. Until then, several deaths had been recorded with episodes of heat stroke as the direct cause of death.
In Santiago del Estero, there were eleven deaths associated with heat stroke. In Entre Ríos, seven more cases were reported that were largely due to cardiorespiratory arrest and decompensation due to the intense heat, as well as a fatal victim due to heat stroke in the district of Avellaneda, and in the province of Salta, a victim was reported due to of sunstroke