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Some Rain, But Overall Deficit

The Rains!

         “A little fun while exploring”

It started raining in Karura on 11 October after a prolonged dry period. Those lucky enough to be in the vicinity of the forest could smell the petrichor.  What’s that, you ask?

Petrichor is the strange and wonderful odour that emanates from newly-wetted soil. The singular smell is comprised mainly of geosmin, a complex organic compound produced by soil bacteria and released in a volatile form, especially after a dry period.

Some believe the extraordinary sensitivity of the human nose to geosmin evolved to help early hominids move quickly to sources of rain, new grass growth and the antelopes that were probably drawn to the spot by the same earthy emanation.

Rainfall Deficit 2016-17



That said, rainfall this past year was down by 30%, resulting in drought conditions in many parts of the country.

Monthly Rainyear 2016-17Karura’s ‘rain-year’ stretches from October through September the next year. The so-called ‘short rains’ often start with some rain in October, as seems to be happening today.

In the recent 2016-17 rain-year, the short rains (November) and the long rains (April) were as expected, but the rest of the months (except July) were well below average. The result was an nearly 300mm deficit in the rain-year’s cumulative rainfall.

Despite poor rains, the forest’s self-sustained micro-climate kept the forest cool and mostly green throughout the prolonged dry months.





Photo by Vince Oylol. Honourable Mention in 2017 Karura Forest Photo Competition