No Storm Nils – IPMA’s clear clarification

Over the past days, Portugal has experienced persistent heavy rain and several weather alerts from the Instituto Português do Mar e da Atmosfera (IPMA). On social media and in some online coverage, you may have seen references to ” Storm Nils”, or even “Depression Nils”. However, according to explanations from meteorologists at IPMA, there is no officially recognized depression named Nils directly affecting Portugal’s weather at this time — even though rain and bad weather conditions will persist.

Our original article used the name “Storm Nils” because that phrase was circulating widely in early forecasts and on social media. As a result, we updated the title to reflect the most accurate and clear description of the weather event: “Atmospheric River brings heavy rain to Portugal.” This title aligns with the actual atmospheric conditions described by IPMA and avoids confusion associated with unofficial naming.

An “atmospheric river” is characterized by intense moisture transport. In other words, it is a long, narrow corridor of concentrated moisture in the atmosphere, characterized by strong horizontal transport of water vapor. When this moist air is forced to rise (for example by a depression or when it reaches the coast), much of that moisture can condense and fall as rain. This heavy rain period can be dangerous due to the saturation in soils in many areas of Portugal and rising rivers.

Update: NILS is the name given by MÉTÉO-FRANCE (French Meteorological Service). Mainland Portugal will not be directly affected by the NILS depression (now called storm by the French authorities). However, it has an associated frontal system that will bring warm, humid air to the Iberian Peninsula on Wednesday, the 11th, resulting in a lot of orange rain alerts. See our article updated. However, Spain and France are experiencing the effects of Storm NILS. 

If not Storm Nils…What is actually happening weather-wise?

This atmospheric river contributes to Persistent heavy rain in mainland Portugal, especially in the North and Center regions, resulting in:

• Orange Rain warnings today (10th of February 2026): Viana do Castelo, Braga, Porto, Aveiro, Viseu, Vila Real, and Coimbra.
• Yellow Rain warnings today (10th of February 2026): Lisbon, Leiria, Santarém, Bragança, Guarda, and Castelo Branco.

For the 11th and 12th of February expect more heavy rain, strong wind gusts in some regions, and coastal events for districts near the coast. The orange and yellow warnings keep changing. Therefore, please check IPMA for a more up to date forecast.

So, for now no Storm Nils, but a period of heavy rain. IPMA meteorologists have explained that a “river of moisture” (often called a rio atmosférico) is responsible for carrying humid air over Portugal, leading to ongoing rainfall.

Stay safe and see this recommendations:

• Stay Informed with IPMA on weather forecast, as these may change in the upcoming hours. Also, check the Portuguese Civil Protection for any important warnings, including those regarding floods.
• Protect your home by clearing gutters and drains to prevent water accumulation
• Avoid unnecessary travel during intense rain
• Do not drive through flooded roads, even shallow water can sweep a car away
• Avoid riverbanks, streams, and low-lying areas prone to flooding
• Do not attempt to cross bridges over swollen rivers
• If driving, reduce speed and maintain extra distance from other vehicles
• Do not take shelter under trees or near walls that could collapse
• Be aware of landslide-prone areas, especially in northern and central Portugal (due to the saturation in soil there is an increased risk of erosion and landslides)
• Evacuate immediately if your home or area is at risk
• Follow instructions from local municipalities and civil protection service

Again, not Storm Nils, but precautions should be taken due to this heavy rain. Flooding risk is high on urban, impermeable roads, and near rivers because water cannot easily soak into the ground, and heavy rainfall can quickly overwhelm drainage systems. Many dams around Portugal are currently very full and, in some cases, reaching their operational limits. Portugal is working with Spain to balance the water discharges.

Second Update: The Coimbra City Council announced tonight, February 10, the preventive evacuation of the villages of Conraria, Cabouco, and the riverside areas of Ceira, Torres do Mondego, São Martinho do Bispo, Ribeira de Frades, Taveiro, Ameal, and Arzila, due to worsening weather forecasts and a significant increase in the flow of the Mondego River. It is estimated that between 2,800 and 3,000 residents may be affected by the measure. Follow the authorities updates and instructions.