Short answers, pulled from the story.
The sky over Venice turned a violent shade of crimson as the sirocco wind drove a thick cloud of Saharan dust across the Adriatic Sea. This meteorological event transformed the Mediterranean into a canvas of red, earning the local name blood rain.
The name sirocco is a linguistic artifact derived from the Arabic word šurūq, meaning the East, and related to the verbal noun šaraqa. This name has traveled through centuries of trade and conquest, evolving into various forms across different cultures including scirocco in Italy and marin in France.
The sirocco is most common during autumn and spring, with peak intensity in March and November when the temperature difference between the desert and the sea is greatest. It is born from warm dry air masses of the Sahara and Arabian deserts pulled northward by low-pressure cells that move eastward across the Mediterranean Sea.
The sirocco is known to cause unease and an irritable mood in people, with scientists finding a correlation between the wind and an increase in hospital admissions for respiratory and cardiovascular problems. The heat and dust brought from the African coastal regions combined with the cool dampness further north in Europe create a climate that is both oppressive and uncomfortable.
When the sirocco combines with a rising tide it creates the acqua alta phenomenon in the Venetian Lagoon where the wind pushes the water of the Adriatic Sea into the lagoon. This event causes the water level to rise and flood the streets of Venice, shaping the architecture and daily life of the people of the city.