The smell of rain - petrichor

6th June, 2017

With warmer weather having arrived in the UK at last, there is still always the chance of rain. And in the summer months there is more of an opportunity to experience the phenomena known as ‘Petrichor’. At its simplest, it’s the smell of rain either as it falls or in anticipation of it falling.

The word comes from the Greek words 'petra' meaning stone and 'ichor' which in Greek mythology refers to the golden fluid that was said to flow through the veins of the gods and the immortals.

What is Petrichor?
The phrase was coined by two researchers at the Australian CSIRO science agency in 1964 article. Their research found that rocks that had been exposed to warm, dry conditions were steam-distilled to reveal a yellow coloured oil that had become trapped in the rocks and soil, a substance they discovered was responsible for the smell. The source of this oil is a combination of oils secreted by plants during dry weather and chemicals released by soil-dwelling bacteria.

How does rain create the smell?
Many people believe they can smell when it is going to rain, and there is evidence to support this. When a higher humidity is experienced as a precursor to rain, the pores of rocks and soil become trapped with moisture forcing some of the oils to be released into the air. But the strongest smell is released when rainfall arrives. Raindrops landing on dusty or clay soils trap tiny air bubbles on the surface which then shoot upward - as in a glass of Champagne - and burst out of the drop throwing aerosols of scent into the air.

Light rain leads to stronger smell
Release of the scent is most prominent when light or moderate rain falls on sandy or clay soils. During heavy rain, the speed of the drops represses the creation of bubbles stopping the release of aerosols.

Prepare for winter ice and snow now before it arrives later in the year
Forecasting for snow and ice thankfully doesn’t rely on our sense of smell. At Ice Watch we have a sophisticated weather forecasting system that means you are alerted in good time. So, to make sure that you are never caught out by severe winter weather disrupting your business, get your winter gritting and snow clearing organised now. Call us today on 01728 633900 for a quote tailored to your needs.

Petrichor is triggered in the warmer months before the rain falls

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