Hail: can it be predicted? Expert answers

In the next few hours, Italy still expects extreme weather events, with heat waves (16 red dot cities) and weather warnings for thunderstorms in most regions of Northern Italy. The Civil Protection then recommends checking the forecasts on the regional sites because, for example, a Milan the alert is orange. Between today and tomorrow, therefore, Italy will still be the emblem of what is extreme events they have become more frequent and more devastating. The fear is that hailstorms with huge grains will be repeated Veneto And Lombardy of recent days, while in the South the prolongation of the heat favors the fireswith temperatures that on the Sardinia and on the middle Adriatic side they reach the 40 degrees.

If the new normal of extreme events strikes everywhere, prudence has not yet become the norm: respect the recommendations of Civil Protection and experts for many it is still only an option, nor are we able to recognize some atmospheric events as really dangerous. But is it possible to realize that the cloud that gathers on the beach will not bring two drops but a storm? And how to tell if hailstones the size of peaches might be raining?

The weatherman Julius Betti, Cnr climate expert and Ampro member, gives some essential indications to avoid taking risks. “First of all – he underlines – citizens must understand that when weather warnings are issued, patience is needed. Although the forecasts are increasingly accurate, they cannot indicate exactly in which area some phenomena may occur, therefore one should not think that if the warning is not followed by the disaster, it is wrong to have issued the warning. It is essential to be cautious, you don’t mess with people’s lives and a false alarm is better than a missed alarm“.

As for hailstorms, these are complex phenomena. “Forecasts may say it could happen hail thunderstorms – explains Betti – but, as mentioned, it is not possible to say precisely where the hail will hit and what size the grains will be. Generally speaking, the size of hail is directly proportional to the amount of energy, but it is a complex phenomenon and forecasters will say that precipitation could be accompanied by heavy hail.”

The possibility of avoiding dents to cars, or worse, bumps on the head, refers to the previous cautionary recommendations. “The anti-hail cannons are silly – says the expert – but some companies have invested in adapting to extreme events and protect their structures. As for individual citizens, the advice is to do not wait for the first drops or the first grain and to take shelter at the first thunder or the gathering of cloudsAnd. One indication that there will be hailstorms is that to the eye the approaching wall of water is very clear, not gray.”

The precautionary recommendations do not change whether you are in the city, by the sea or in the mountains: “First of all you have to find out about the warnings and weather forecasts on institutional sites such as those of the Arpa and the regional civil protections – Betti reiterates – in the mountains you should not venture on excursions with a yellow alert and everywhere we need to be aware that, no matter how much experts and institutions can get involved it is the citizen’s responsibility to exercise the utmost prudenceto”.

In this regard, it is useful to remember the recommendations of the National Civil Protection in the event of showers and rain:

• Outdoors: if you are near a stream, you must choose an area away from the stream bed and raised above the level of the stream itself, as well as sufficiently distant from steep or unstable slopes, because heavy rains could cause landslides.

• In the city: the dangers derive from sudden flooding because the sewage system is unable to dispose of considerable quantities of water. For this reason it is advisable to avoid subways and underpasses so as not to find yourself submerged in water with the car. Basements, lower floors, garages should also be avoided, as they are at high risk of flooding during heavy downpours.

• If you are driving: even if there are no floods, wet asphalt reduces both road holding and brake efficiency. In the event of a strong storm, which rarely lasts more than half an hour, stop at a rest area.

• In the event of hail, what has already been said for rain showers applies, because the danger derives from the slippery road surface and greatly reduced visibility. Also in this case you have to be patient and stop: the duration of a hailstorm is typically quite short.