Ash Falling on Alerces

In August 1991, Chilean Patagonia's 1,935-meter Volcán Hudson spewed an ashfall of more than five cubic kilometers that carried into the South Atlantic Ocean and even across the Pacific to Australia. In the immediate area, around the Aisén region town of Chile Chico and its Argentine neighbor Los Antiguos, more than 1.5 meters of ash accumulated in some spots. It fouled the water, ruined crops, killed livestock that could not reach forage, and drowned forests of southern beech such as the one depicted here along the Río Murta.

Farther north in Chilean Patagonia, where the narrow endemic alerce (false larch) is the signature tree species, a similar event is forcing at least a partial evacuation of the port of Chaitén (population about 4,000). According to the Smithsonian Institution's Global Volcanism Program, the town's namesake volcano, an 1,122-meter peak only about ten km away on the edge of the Parque Pumalín conservation project, is spewing plumes of ash up to 55,000 feet above sea level. Fortunately there is no snow on the volcano - because the peak drains toward the town of Chaitén, there would be serious flood danger. The caldera, though, does have two small lakes that could drain if the caldera were breached.

Again according to the Smithsonian, Chaitén's last known eruption was 7,420 B.C., plus or minus 75 years, so this was unexpected. Early reports, in fact, were that the eruption came from snow-covered Michimahuida, pictured here; an eruption on Michimahuida - the last was in 1835 - could cause major snowmelt and flooding.

Meanwhile, the prevailing westerlies are carrying ash toward the town of Futaleufú, Chile's whitewater rafting capital, and across the border into the Argentine city of Esquel (which canceled school classes yesterday), east of Los Alerces National Park. According to one Internet newsgroup report, some Futaleufú residents were wakened repeatedly by tremors during the night, and went outside to find the town covered by what appeared to be snow but, on closer inspection, was ash. There are photos of the town online at the Chile forum All Chile.

UPDATE: As of early Saturday evening, Chilean time, Chris Spelius of the Expediciones Chile kayaking and rafting company tells me that his wife is trapped in their Futaleufú house with the windows taped, without water and with diminishing food supplies. According to Chris, "No vehicles are moving as the volcano dust conducts electricity and ruins the alternators. There are about 50 vehicles abandoned on the road between Chaiten and Futaleufú ... " The border crossing to Argentina is open, but "but no one wants to take a vehicle since most vehicles do not last 30 miles in the dust."