Chile, Argentina: Adverse weather forecast to continue across much of Chile and parts of western Argentina through at least July 15 /update 2

Event

Severe weather is forecast to continue across much of Chile and parts of western Argentina through at least July 15. Strong winds, heavy rainfall, and snowfall are forecast across parts of Chile. In western Argentina, snowfall is expected in parts of Mendoza, Neuquen, Rio Negro, and San Juan provinces. The adverse weather is causing disruptions in some areas as of early July 14. Rainfall totals of up to 4.5 cm (1.7 inches) and snowfall amounts of 2-5 cm (0.8-2 inches) over higher ground are expected in parts of central Chile. Snowfall amounts of 5-10 cm (2-4 inches) are possible in elevated parts of northwestern Mendoza and southwestern San Juan provinces in Argentina.

As of July 14, the Chilean Meteorological Directorate and Argentinian National Meteorological Service (SMN) have issued the following weather warnings:

• Orange heavy precipitation warnings (the middle level on a three-tier scale): Across Coquimbo and parts of Atacama regions in Chile.

• Orange snowfall warnings: Parts of northwestern Mendoza and southwestern San Juan provinces in Argentina.

• Yellow precipitation warnings: Parts of Atacama and Coquimbo regions in Chile.

• Yellow snowfall warnings: Parts of Antofagasta, Atacama, Biobio, Coquimbo, Maule, Metropolitana, Nuble, O'Higgins, and Valparaiso regions in Chile; and parts of western and southwestern Mendoza, western and central Neuquen, and western and central Rio Negro provinces in Argentina.

• Yellow frost warnings: Parts of Aysen and Magallanes regions in Chile.

• Yellow strong wind warnings: Parts of Antofagasta, Arica-Parinacota, Atacama, Coquimbo, O'Higgins, Taracapa, and Valparaiso regions and the Juan Fernandez Archipaleago in Chile.

Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

The Los Libertadores Border Complex in the Andes between Chile and Argentina remains closed as of July 13 due to heavy snowfall in the area since July 9. Hundreds of people had to be rescued after around 250 vehicles became stranded near the border crossing July 9-10. The Pehuenche crossing near Malargue was also closed as of July 13. Thousands of people have been isolated due to snowfall in parts of Biobio and La Arauncia regions in recent days. Flooding has also been reported in parts of Biobio and O'Higgins regions. Authorities in O'Higgins region have closed roads leading to mountain passes and suspended operations at the ports of Pichilemu and Bucalemu July 13 due to the adverse weather. Transport authorities in Neuquen Province in Argentina closed several Andean routes overnight July 13-14 due to the forecast snow levels in the area. The Pino Hacado and Paso Icalma border crossing have also been temporarily closed due to the risk of snow and ice on the roads.

Hazardous Conditions
The storms could produce rounds of heavy precipitation (including rain and snow), strong winds, and isolated thunderstorm activity across parts of the affected area. Where precipitation falls as rain, flash and areal flooding is possible. Such flooding is possible in low-lying communities near watercourses and other large bodies of water, as well as in urban areas with easily overwhelmed stormwater drainage systems. Sites located downstream of large reservoirs may be subject to flash flooding after relatively short periods of intense rainfall.

Precipitation could fall as snow in the higher elevations over the coming days. Wind gusts could cause blowing and drifting snow; decreased visibility is likely in mountainous areas. Rain-induced landslides cannot be discounted in areas of elevated terrain; there is also the possibility of avalanches in mountainous areas where the snowpack has become unstable due to heavy snowfall. Power outages could occur throughout the affected area.

Transport
Floodwaters and related debris may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around the affected area. Flooding in urban areas could also result in significant traffic congestion. Heavy snow will likely make driving hazardous in some areas; authorities could implement temporary road closures or detours in such locations. Mountain passes and tunnels could be closed as a precautionary measure during periods of intense snowfall.

The disruptive weather will likely cause some delays and cancellations at airports in affected areas. Authorities may temporarily suspend port operations along the west coast of Chile if strong winds trigger hazardous sea conditions, impacting freight and passenger maritime traffic. Flooding or snow could block regional rail lines; freight and passenger train delays and cancellations are possible in areas that see heavy rainfall and potential track blockages.

Disruptions triggered by inclement weather and resultant hazards, such as flooding or avalanches, could persist well after conditions have improved - it could take days before any floodwaters recede and/or officials clear debris. If there is severe damage to infrastructure, repair or reconstruction efforts may result in residual disruptions.

Advice

Monitor local media for weather-related updates and advisories. Confirm all transport reservations and business arrangements before traveling in the affected area. Seek updated information on road conditions before driving or routing shipments through areas where severe weather is forecast; plan for possible supply chain disruptions throughout the affected areas. Stay away from elevated streams, creeks, and other watercourses that are prone to flash flooding. Do not attempt to navigate flooded roadways. Exercise caution in elevated terrain due to the threat of landslides, as well as mountainous regions where avalanches pose a threat. Charge battery-powered devices in the case of prolonged electricity outages.

Resources

Argentina National Meteorological Service (SMN)
Chilean Meteorological Directorate