Those attending the opening session of the Dublin Horse Show at the RDS last Wednesday will vividly remember that now-famous thunder shower. For many of us it was the heaviest rain we are ever likely to experience.
And those who watched the events on television in the comfort of their living rooms may have been mildly amused at the sight of hundreds of people madly dashing to find the nearest canopy. The dashers, naturally, were trying to stay as dry as possible, but were they adopting the most effective strategy towards this end?
The problem is as old as homo sapiens and dates from the time when some distant ancestor first had the bright idea of walking upright.
In heavy rain, should one run helter-skelter to the nearest shelter, thereby suffering a soaking down the front? Or is it better to take one's time, encountering fewer raindrops in any given interval, but enduring the unpleasantness for rather longer? Which option leaves the individual least wet?
Modern science has provided an answer to this serious dilemma.
Investigating the problem, researchers assumed for the purpose of their argument that the rain falls vertically, and that its intensity is constant over time - conditions both broadly fulfilled at the RDS on Wednesday last.
A person standing still when exposed to such a downpour will have the rain falling directly on his horizontal surfaces; if, on the other hand, he moves, he will also collide with extra raindrops in his way.
Obviously, if the subject of this experiment just stands still, he or she will get very wet indeed because the rain will fall on him indefinitely. But if he moves, the total amount of water encountered turns out to decrease rapidly as he increases his rate of progress to a brisk walk, for the simple reason that the faster he travels the quicker he reaches shelter.
But surprisingly perhaps, beyond a brisk walk any further increase in speed has very little effect upon how wet someone gets: if he runs like mad, he will reach the shelter very quickly, but at this higher speed he will have collected more raindrops on the way, and consequently experienced a more serious wetting down the front.
Bearing in mind that we wish to achieve the best result with a minimum of effort, the best tactic, it seems, is to head for the nearest shelter at about 6 m.p.h., or slightly more than walking pace. If you move more slowly, you will catch more rain, and to go any faster is simply just not worth the extra energy required.