Red Rain

Massive Red Rainshowers:
Ehrenburg and Darwin

There is a particular form of red rain that has most often been attributed to sand from the Sahara being carried over southern Europe and northern Africa. Ehrenburg, who studied red rains and blood rains, examined the deposits of a good number of contemporaneous cases and extended the range of red rains to include "the adjoining portion of the Atlantic, and the corresponding latitudes in western and middle Asia."

Ehrenberg estimated that 720,000 lbs. of matter fell during a single shower, on October 17, 1846, near Lyons, France; and that 1/8th of the fall--90,000 lbs.--was composed of microscopic diatoms (Passat-staub und Blut-regen, 1847; and Amer. Journal of Science, II. xi. 372).

Interestingly, he was able to find over three hundred species of organisms (mostly diatoms) which were not thought to be African. Fifteen were South American. And the origin of the dust was unknown. The size of these red rainstorms should not be underestimated. One such shower at Cape Verdes was described by Charles Darwin, who estimated that it covered more than 1,600 miles. Furthermore, Darwin determined that the red rain reached a distance of 800 or 1,000 miles from the coast of Africa. James Dwight Dana, in his Manual of Geology (3rd. rev. ed., 1880, pp. 633-635), points out that--based on these figures--an area of more than a million square miles had been showered upon by this single red rain. At the other extreme is the case of the 1860 red rain in Sienna that, on four occasions, fell onto "exactly the same quarter of town." Even if winds caused these red rains, the wide range of the breadth of these sanguine showers is intrinsically anomalous.

Naturalist Philip Henry Gosse also accepted that real red rain sometimes falls, although not necessary blood-red rain. He cites the case published in the London Times on January 24, 1861, by Mr. Giovanni Campani, a professor of chemistry at the University of Siena. Mr. Campani describes a red rain that fell on December 28, 1860, at 7:00 a.m. In the northwestern part of the city, the locals watched as there was a great two-hour long shower of reddish rain. At 11:00 a.m. there was a second shower of the red rain and a third at 2:00 p.m. On December 31st and January 1st the phenomenon was again recorded. Gosse comments that the strangeness of the event was added to by the fact that every shower of red rain fell only in the northeastern quarter of town. The area in which the red rain fell could be determined fairly accurately, so much so that it was known that the red colored rain stopped at approximately 200 meters from the meteorological observatory, which collected only colorless rain at the same time that the red rain fell so nearby.

The red color of the rain became less pronounced each time it rained, and--at its reddist--it was said to look like watered-down weak red wine. These European red showers are generally explained as being composed of red sand and dust carried from the Sahara and elsewhere, and deposited in rain.


İMark Chorvinsky, 1995