The Copahue volcano has cut loose with a blast of ash and gas along the Chile-Argentina border.
The eruption began Saturday morning, prompting the Chilean government to hoist a red flag for the Biobio region, the BBC News website said.
Authorities in Argentina cautioned local residents.
NASA satellite images captured the trace of the ash cloud as it streamed east-southeastward over the Argentina desert.
The eruption of the 10,000 foot Copehue volcano was its first since 2000.
The blast was apparently short-lived and relatively small, according to the Eruptions blog. Volcanologist Erik Klemetti said the eruption was driven more by exploding steam rather than fresh lava.
Klemetti also indicated that the Copehue blast was dwarfed by the powerful 2011 outbursts at Puyehue-Cordon Caulle, Chile.
The Puyehue-Cordon Caulle blasts spread thick layers of ash along the Chilean and Argentinian Andes. Costly damage and loss of income were suffered by mountain resorts, such as those of Bariloche, Argentina. Ranchers also suffered losses.
Ash fall extended eastward into the Argentina Pampas, even reaching Buenos Aires, where many flights were canceled or diverted.
A 1992 photo of the summit of Copehue volcano, straddling the Chile-Argentina border; Callaqui volcano towers in the distance. (Smithsonian National Museum/University of Chile/Oscar Gonzalez-Ferran)
The plum rains are known as "meiyu" in China, the "baiyu" or "tsuyu" in Japan, and the "jangma" in the Koreas. The heart of the plum rain season stretches from early June to mid-July, with a tendency to shift south to north across the affected area.
In the wake of the mid-June cloudbursts, most of Pakistan to northwestern India last week saw a return to dry, hot weather typical of the weeks leading up to the Monsoon onset. It was as if the Monsoon withdrew to its "normal" position for the latter half of June.
The 38.5 degree C (101 degrees F) reading Tuesday in Ajaccio, Corsica, may have been tops in Europe.
Monsoon Onset was June 13th, 2013, in Delhi, almost two weeks earlier than average. The June 15th onset at Karachi and Islamabad was more like three week ahead of schedule.
In Pakistan, hit-or-miss downpours missed the Sindh capital, Karachi. One did hit Pad Idan, where it left 60 mm of rain Wednesday. This was more than 20 times greater than the normal June rainfall.
It is still possible that this scenario is over wrought as to the intensity and spread of rain in Pakistan and northwestern India. However, it is the hunch of the present forecaster that some very unusual weather is going to unfold in the Subcontinent during the next week!