On June 4th, Patagonia's Puyehue Volcano erupted for the first time in more than fifty years. The eruption has been widely reported from many sources and has resulted in flight cancelations in Chile, Argentina and other parts of the southern hemisphere. Our thoughts go out to those living close to affected areas, but there is little doubt that that the region will soon be back to normal. Rance Rathie - owner of Patagonia River Guides - sent us a very detailed and thorough update on the eruption, and we have borrowed the following information from his report.
Initially, during the first hours of the Puyehue eruption, the volcano deposited mostly small pumice stones, and for the next two days began sending finer particles and ash to the area around Bariloche and neighboring Villa la Angostura. Anywhere from a “light dusting” to as many as thirty centimeters (twelve-inches) of ash and volcanic material can be found as far south as El Bolson to as far north as Montevideo Uruguay.
On June 6th, the wind shifted and ended up blowing from the southwest (it blew from the northwest for the first two days). This change in wind changed the direction of the cone of ash, and some (mostly fine ash) was deposited to the north of Bariloche and into the neighboring Neuquen Province. The areas around San Martin de los Andes and Junin de los Andes were slightly affected, and on-the-ground reports state that there was a half of a centimeter of ash or less in and around the town of San Martin (the town closest to the volcano to the northeast). The farther away from the volcano the less the amount of ash reported. Fortunately, it began raining immediately afterwards in the valleys and snowing at higher elevations. The rainfall continued for a week and much of the airborne ash quickly abated and the process of “washing” the ash has already occurred. The eruption has not ceased, but has significantly decreased its activity. In comparison, the Chaiten Volcano eruption continued for several months in 2008 but deposited little ash after the first two weeks. Initially, during the first hours of the Puyehue eruption, the volcano deposited mostly small pumice stones, and for the next two days began sending finer particles and ash to the area around Bariloche and neighboring Villa la Angostura. Anywhere from a “light dusting” to as many as thirty centimeters (twelve-inches) of ash and volcanic material can be found as far south as El Bolson to as far north as Montevideo Uruguay.
So what are the expected long-term effects? No one really knows, but Puyehue volcano erupted in 1960 and the material released in the previous eruption is similar; therefore, similar effects are expected, which leads those in the area to believe that there won’t be any long-term environmental problems. And, if we look back only a few years to the Chaiten eruption in 2008, we can make certain assumptions about the Bariloche area. From an angling perspective, the volcano erupted at exactly the right time of the year — the end of the trout season. The general flyfishing season around Bariloche closed on June 1st rain and snow are normally expected for the next five months, which should wash a good percentage of the ash down the system. If this event is anything like the Chaiten eruption, fishermen will find that by the time the season opens in November, most of the ash will have been carried away by the winds of Patagonia and by the Rio Limay (the largest watershed in Northern Patagonia). By the time most American anglers show up (the majority arriving after Christmas), there will be little signs the event ever took place. Aside from Patagonia River Guides, we have heard from all of our other lodge operations in both Argentina and Chile, and everything looks good for the coming season!