Viana with 7,944 electrical discharges in 50 days of thunderstorms. More than 1,000 fell to the ground

The district of Viana do Castelo was the second in the country with the most days of thunderstorms during the year 2023, with the Portuguese Institute of the Sea and Atmosphere (IPMA) detecting around 8,000 atmospheric electrical discharges over the soil of Alto Minho.

In the discharge report corresponding to last year, to which O MINHO had access, IPMA notes that “it was in the region of Trás-os-Montes and Alto Douro and Alto Minho that the greatest number of thunderstorm days occurred, represented by the districts from Vila Real (54 days), Bragança (50) and Viana do Castelo (50).

In the district of Viana do Castelo, 1,064 electrical discharges were recorded that reached the ground and 6,880 discharges that occurred between clouds, points out the same report.

In terms of municipalities, Arcos de Valdevez was the most affected, occupying sixth place in the national table, with 32 days of thunderstorms where 2,011 atmospheric electrical discharges were recorded, 267 of which reached the ground.

According to the IPMA report, “thunderstorms are generally associated with cumuliform clouds, namely cumulonimbus, isolated or organized in mesoscale convective systems, which can give rise” to electrical discharges, “intense precipitation, strong wind gusts and hail ”.

“This phenomenon results from the separation of electrical charges within a cloud, due to the collision between particles, distributed within the cloud according to the size and type of particles and the dominant ascending or descending air currents”, adds the IPMA.

Lightning can reach 20 kilometers in length and 40 thousand kilometers per second, reaching an electrical current greater than 100Kamp.

Some of the rays reach the earth, the vast majority of which have negative polarity, but the most common are between clouds. Lightning with positive polarity, in turn, is usually associated with a greater discharge of energy, causing more audible thunder.

The IPMA Atmospheric Electrical Discharge Network has five detectors in mainland Portugal, one of them located next to Braga aerodrome, has been operating since June 2002, detects and locates “atmospheric electrical discharges (lightning) in the continental territory and adjacent oceanic areas”.