[News] Ecuador has had anomalous winters since 1991. What phenomenon affects the Sierra?

[#Steeven.™]

Winter not only came later, but also shows unusual behavior with less rain, high temperatures during the day and very low at night, so frosts occur in the early morning. But this is not a new 2020 phenomenon and is directly related to the La Niña phenomenon.

Ecuador has recorded more deficit of rains for the winter season since 1991 compared to last month. The Hydrometeorological Studies and Research Directorate of the National Institute of Meteorology and Hydrology (Inamhi) reached this conclusion, whose staff carried out an analysis of the behavior of winter in the Sierra region at the request of EL COMERCIO.

After analyzing the months of September, October and November from 1991 to 2019 versus September and October of this 2020, the technicians explained that at the end of October there was lower rainfall in the 29 years analyzed than in this year.

This was verified in five of the eight stations in the Sierra with available historical information. At the San Gabriel-Tulcán station, for example, there was a greater rainfall deficit in 1991 and 2001; While, in the capital, in Iñaquito, in addition to these two years, it also happened in 2000, 2009 and 2015.

The solid red line presents the accumulated daily precipitation from September 1 to October 31, 2020. The dotted black line indicates the normal or expected range for the period 1991-2019 (29 years). The solid gray lines are the daily accumulated for each year for the last 29 years.

 

In La Tola, also in Quito, this behavior was limited to three years: 1994, 2005 and 2013. In the case of the Izobamba station, the precipitation deficit began in September of this year. However, the precipitation deficit during September, October and November was much more marked in 2001 and 2009.

The solid red line presents the accumulated daily precipitation from September 1 to October 31, 2020. The dotted black line indicates the normal or expected range for the period 1991-2019 (29 years). The solid gray lines are the daily accumulated for each year for the last 29 years.

 

The meteorologist, Carlos Naranjo, explains that, since the past decade, climatic and meteorological patterns have been undergoing changes from year to year all over the planet, not only in Ecuador.

Historically, the common cycle of the rainy season in the Sierra began in late September or early October; in November and December it decreased slowly, only to increase again in January and February, reaching its maximum in March in some places and in April in others.

People got used, for example, to the well-known "Cordonazo" occurring in early October, now there are delays. Also, the rains were distributed throughout the city of Quito, from south to north, currently rainfall is specific and by areas.

This is replicated in the rest of the provinces of the Sierra, where the rains are not distributed throughout the month, as before, but are concentrated in a number of days, so the level is lower than expected. Now there are fewer days of rain, but very intense, emphasizes Naranjo.

This decrease in rainfall that has been experienced in recent months, according to Inamhi, responds to an alteration in the wind regime, which should have a greater contribution of humidity, especially towards the Amazon and the Inter-Andean Alley.

Anomalous conditions have been evidenced due to the entry of cold and dry air masses coming, mainly, from the Pacific area and this causes the formation of clouds to be limited, the entry of humidity and, consequently, there is an absence of rain frequent.

The concentration of rainfall in two or three days has also caused considerable flooding. The ECU-911 recorded between September 1 and November 12, a total of 58 floods. Of this amount, 40, that is, 69%, were concentrated in Pichincha.

The World Meteorological Organization has reported that the country would be under the effect of La Niña, which is why it considers that November, December and January would be months with a deficit of rainfall. Rains are not ruled out, but at lower values than normal.

The National Committee of the Oceanographic and Antarctic Institute of the Navy (Erfen) agrees and adds that the La Niña event has caused colder than normal waters off the coast of Ecuador, limiting the entry of moisture from the north.

For Naranjo, this phenomenon is installed in the Pacific area and is a total conditioning factor that directly affects Ecuador and Peru with occasional but intense rains, clear skies at night and early morning and that generates a drop in temperature in the early morning. generating frosts, which impact agriculture and livestock.

In Colombia, he adds, the opposite happens: more rains.

Due to the low moisture content on the surface and the higher average speed of the winds, there are other extreme events such as high temperatures, even at extremely high categories, and in turn, forest fires have been generated.

From October 1 to November 13, there have been 717 fires in 10 provinces of the Sierra and three of the Amazon, according to the report of the General Secretariat of Risks.

The provinces with the most number of events have been Azuay, Cañar and Loja, but if we take into account the number of hectares of burned vegetation cover, the most impacted localities are: Loja, Pichincha and Azuay. In total, 12,071 hectares have been burned.

This number of fires corresponds to 34% of the total events that occurred up to November 13, which add up to: 2,121, with a total loss of 25,227 hectares.

According to the characteristics of the winds, one of the main triggers of forest fires is an average speed of 10 meters at 2.5 m / s. 86% of the incidents correspond to level 3 of affectation, that is, greater than or equal to 10 hectares.

Only in this month of November there have been 16 fires with the greatest impact, mainly in the Austro.

Since 2015, fires in the country have been increasing and the highest peak was in 2018 with 4,300.