Summit County Citizens Voice

Good fishing in Peru often means good powder skiing in Montana

New research shows links between La Niña conditions and weather in Montana.

By Summit Voice

SUMMIT COUNTY — For many climate buffs, a recently reported link between ocean temperatures off the coast of Peru and weather in Montana won’t come as a surprise. The effects of El Niño and La Niña on the North American storm track are well-known, but the new study from Montana State University helps pinpoint the connection.

Joseph Caprio analyzed 100 years of data to show that, when the average surface temperature of the ocean near Peru is warmer than normal from November through March, fishing off the coast of Peru will be poor and Montana will experience El Niño from the following December through June, with generally warm and dry weather.

If the average surface temperature is cooler than usual from November through March, fishing off the coast of Peru will be good and Montana will have a cool, wet spring, like the one experienced this year during La Niña, Caprio said.

“Since El Niño sea surface temperature anomalies tend to persist for many months and have predictable climatic associations, it is prudent to undertake research to understand how El Nino affects extremes of weather for individual locations in order to provide useful information for decision makers,” Caprio said in a paper he published in the Intermountain Journal of Sciences.

Peruvian fishermen knew hundreds of years ago that ocean temperatures affected their livelihood. And scientists have long known that weather around the globe is linked to El Nino in different parts of the world. Meteorologists with the National Ocean and Atmospheric Administration make long-range forecasts by monitoring sea surface temperatures, atmospheric pressure, wind, air temperatures and cloudiness in various areas of the Pacific Ocean.

Caprio focused on the sea-surface temperatures in the area that’s associated with Montana weather. That area is off the Peruvian coast and near the equator. It covers about 550 miles from north to south and 4,100 miles east to west.

Caprio specifically wanted to determine the effect of El Nino on extreme daily temperatures and precipitation in Montana.

Compared to normal years, El Nino years tend to have about 20 percent more days with extreme high daytime temperatures, 20 percent fewer days with extreme low nighttime temperatures and 20 percent fewer days with high precipitation amounts, Caprio said.

“An increase or decrease of extreme daily weather occurrences can impact natural resources and a wide range of human activities including agriculture, forestry, recreation, construction and other businesses,” Caprio added.

Filed under: climate and weather, El Niño, La Niña, seasons Tagged: | climate, El Niño-Southern Oscillation, El Nino, La Niña, Montana, Montana State University – Bozeman, Pacific Ocean, Peru, Summit County News, weather