Chile, Argentina: Adverse weather forecast across much of Chile and parts of northwestern Argentina through at least July 12

Event

Severe weather is forecast across much of Chile and parts of northwestern Argentina through at least July 12. Strong winds, heavy rainfall, snowfall, and thunderstorms are forecast across parts of Chile and snowfall and strong winds are expected in neighboring parts of Argentina. The adverse weather is causing disruptions in some areas as of early July 11.

As of July 11, the Chilean Meteorological Directorate and Argentinian National Meteorological Service (SMN) have issued the following weather warnings:

• Orange heavy rainfall warnings (the middle level on a three-tier scale): Parts of southwestern Atacama and northwestern Coquimbo regions in Chile.

• Orange frost warnings: Parts of eastern Magallanes Region in Chile.

• Yellow snowfall warnings: Parts of western San Juan Province in Argentina.

• Yellow heavy rainfall warnings: Parts of western and central Atacama Region and across Biobio, Coquimbo, Maule, Metropolitana, Nuble, O'Higgins, and Valparaiso regions in Chile.

• Yellow thunderstorm warnings: Parts of southeastern Atacama and northern Coquimbo regions in Chile.

• Yellow frost warnings: Across eastern and central Aysen and Magallanes regions in Chile.

• Yellow strong wind warnings: Parts of eastern, central, and southwestern Atacama, eastern and western Antofagasta, southwestern and central Los Lagos, and eastern and western Taracapa in Chile; and parts of western Catamarca, western and central Jujuy, western La Rioja, and western and northern Salta provinces in Argentina.

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

Hundreds of people had to be rescued and placed in temporary accommodation after being stranded in heavy snowfall near the Los Libertadores Border Complex between Chile and Argentina in the Andes July 9. The border crossing remained close July 10 and will reopen once conditions improve. An active weather front brought heavy rainfall, strong winds, and snowfall to other parts of Chile July 9-10, causing flooding, power outages, and transport disruptions in parts of the country. As of July 10, over 24,000 people remained without power across the country. More than 6,000 people across Chile were stranded due to heavy snowfall. The majority of these were in the Alto Biobio Commune in Biobio Region and across parts of La Araucania Region.

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