What is the mistral wind and why is it the greatest enemy of the Baix Ebre fire?

The north wind that blew between yesterday and early this afternoon at both ends of the country strengthened, especially at dawn, with locally strong gusts on the Ebro. Firefighters have explained that they have had to fight the flames with wind gusts of 90 km/h in the area of the Paüls fire, in Baix EbreA very adverse situation. The wind has pushed the fire southeastward persistently and uncontrollably, with very low humidity that has remained around or below 40%, further drying out the land battered by the extreme heat experienced in recent weeks. The only positive factor is the temperature, which has dropped significantly and was clearly below 20°C in this area by early morning. A cool morning doesn't make up for the weather conditions that have generally been very adverse due to the windy conditions until this afternoon.

The good news is that the long-awaited breeze has arrived since 4:00 p.m., bringing a change in the situation. This wind, which is expected to blow with weaker gusts from the southeast to the northwest until the evening, the opposite direction to the mistral. Therefore, it could slow the spread of the flames and push the fire toward already burned ground, which will facilitate the work of firefighters, especially on the right front located to the south. However, the left flank is a cause for concern, as this shift in the wind could shift toward the heart of the Els Ports mountain range. It will be a maritime wind that will significantly increase humidity and lower temperatures, which will not rise as much as yesterday and will mostly remain below 30°C. And there is a possibility that some showers could reach the Baix Ebre between early this morning and Wednesday morning.

What is the mistral wind and why is it the great enemy of the Baix Ebre fire?

The mistral is a very common wind in Terres de l'Ebre. It's a northerly wind that channels through the Ebro River valley, where it gathers strength and dries out, blowing from the northwest to the southeast. It carries all the warmth from the interior of the Peninsula to the Catalan coast and pre-coast. Therefore, all these factors make this phenomenon very dangerous in the event of a fire. the rule of three 30, which is the fatal combination that facilitates the formation of large fires in summer: low humidity (around 30%), temperatures around or above 30ºC, and wind gusts exceeding 30 km/h. These conditions have been met in recent hours, especially on Monday.

When the north wind reaches our house, it does so with force in the far corners of the country due to the orography: in the south it is called the mistral; in northern areas, such as Empordà, it is called the tramontana. In this specific case, a cold front crossed us over the weekend, opening the door to this north wind, which, while not particularly intense, was enough to push the flames out of control.

Heat at bay and fewer showers in the rest of the country

Beyond the fire zone, the rest of the country is expected to have a moderately warm and less unstable Tuesday, following new, very irregular showers and thunderstorms between yesterday afternoon and early this morning in areas of the northeast and the coast and pre-coast of Barcelona and northern Tarragona. Of note were 24 l/m² in Parets del Vallès, 13 in Caldes de Montbui, and 11 in Granollers and Torredembarra. Rain will not repeat today, although light, local showers or light sprinkles are not ruled out in the afternoon in the northeast, especially in mountainous areas of the Girona region. Throughout the day, skies will be variable, with sunshine combined with some cloudy periods in coastal and pre-coastal areas, as well as in the Balearic Islands, where some drizzle is not ruled out. Showers will resume on the southern coast starting tonight.

The night was generally cool, with temperatures well below 20°C in most of the country, and even below 10°C in the Pyrenees. A morning of warmer weather in the north and in mountainous areas. Only lows slightly above 20°C were recorded in coastal areas. Highs will drop a little further, especially on the coast and pre-coastal areas of Barcelona and Tarragona, with no change elsewhere. They may rise slightly on the Costa Brava, where the Tramuntana wind will blow throughout the day. The mistral wind will eventually disappear over the Ebro River starting in the early afternoon. Many highs will hover between 26 and 31°C, slightly higher in the West Bank and the southern interior, and lower in mountainous areas.

No further warmer weather in sight.

Temperatures will remain in check until Wednesday or Thursday. While they appear to be rising and warmer in the following days, there are currently no signs of hot weather or heat waves in sight. The early hours of Tuesday and Wednesday will be marked by renewed showers and thunderstorms in Castellón, the Tarragona coast and pre-coast, and southern Barcelona. Some local downpours are not ruled out. The instability will not completely subside in the coming days. Some weather models even indicate that we could see a flurry of showers and thunderstorms this weekend, resulting from a buildup of cold air. We'll have to confirm.