I came across this from a few years ago – we had a lot of rain rrecently, but I’ve no idea what type it was
I was writing about the British fascination with weather the other day… and then today I came across some interesting facts from the Meteorological Office… did you know there is an actual word to describe the smell of rain after a long period of dry summer weather? Petrichor… and I know exactly what it smells like, and just thinking about it takes me back to an afternoon in 1970; it must have been June or July and it was the last day of term, or the day we finished our exams, or the day our results came out… We were in Manchester, at what was then the new Polytechnic (‘the Rolls Royce of Polytechnics‘ the director, Dr Smith described it… and we know what happened to Rolls Royce…) I was sharing a flat with a friend, and all our other chums came round… maybe we had been to the pub, maybe we’d had some drinks at the student union, or at home, maybe we weren’t drunk but drunk with joy at finishing the first year!
It had been tremendously hot, and we had spent the past couple of months revising, working, finishing our first dissertation, doing exams, working really hard; we had a good work ethic I think, looking back, and also we had a much fuller timetable than students have these days, lectures, seminars, tutorials, contrasting studies… we were in college every day for long hours, and then studying in the work rooms, or library, or the Manchester Central reference Library, or at home…
We were free! It was done! We had a two month holiday! It was roasting hot, and then the rain came down and we went outside into the street and cavorted about shouting and laughing and singing in the rain (yes we actually did!) Just thinking about it I can smell the scent of the rain hitting the road and pavements, and almost hear us shouting and acting the fool! So that is petrichor.
The title of this post is ‘Three types of rain’, which are frontal, orographic and convective:
- Frontal rainfall is a type of condensation that occurs when a cold front meets a warm front. Warm air is less dense than cold air; when the two air masses meet, warm air is forced over the cold air, because it is less dense.
- Orographic rainfall is is produced from the lifting of moist air over a mountain. Moist air rises and cools, producing orographic clouds, which are the source of the rain.
- Convective rain happens when warm air deflected from a landform rises and forms rain clouds.
… and rain drops can be as big as 6 mm in diameter… which is about the average size of a pea… so maybe we should say ‘it’s peaing it down’, not ‘its peeing it down’.
Here are some other facts about British rain from the Met Office:
- the longest consecutive number of days of rain was 156 in the year 2000
- the driest location is Shoeburyness in Essex, with on average 495 mm of rain…
- … and the wettest in Cumbria, Seathwaite with 3304 mm
- the most rain in an hour was the 12th July 1901 in Maidenhead in Berkshire, with a fantastic 92 mm…
- … and the most rain in a day, 24 hours, was again in Cumbria, on the Honister pass on the 5th December, 2015, 341.4 mm – that is a heck of a lot of rain!
There is loads or other interesting information here:
Lois Elsden 