Flights to and from Argentina and Uruguay are starting up again after a weekend windstorm kicked up so much ash from a Chilean volcano that airports closed in both countries' capitals.

Flights to and from Argentina and Uruguay are starting up again after a weekend windstorm kicked up so much ash from a Chilean volcano that airports closed in both countries’ capitals.

Air travel in parts of southern South America has been problematic since the Cordon Caulle volcano began erupting in June, but this time it wasn’t a new eruption grounding flights. It was winds gusting up to 75 mph (120 kmh) that kicked up tons of ash accumulated across Patagonia. Now with snow melting in the Argentine spring, there’s nothing to hold down tons of ash. A huge cloud enveloped Buenos Aires and Montevideo in gritty gray dust on Sunday, shutting down major airports.

Hundreds of flights in and out of Uruguay and Argentina were grounded Sunday, but a change in the winds cleared the skies by Monday.