Beschreibung:
Abstract. - In the third decade of march 1973, exceptional rains caused serious floods in the north of Tunisia. These rains can be explained by a sudden advection of cold air above the east of Maghreb and by its stagnation in the shape of a « drop ». This situation, a classical one in Tunisia, produces important rains only when the atmospheric circulation in altitude is submitted to a blocking, productive of a great instability.