April 18, 2016
Volcanoes, Atmospheric Rivers and Other Weird Weather
by Historical Climatologist Evelyn Browning-Garriss & Climatological Analyst James J. Garriss
Have you enjoyed shivering your way through the latest bout of volcano weather? Early April, springtime, was really cold in parts of the East. Two cold fronts whizzed in and sent temperatures plunging to record lows. It was a gift from Mt. Pavlof in Alaska.
Scientists have known for a long time that powerful volcano eruptions alter weather. When the debris goes high enough, it blocks incoming sunlight, cooling temperatures and changing air pressures and wind patterns. On March 27 and 28, Alaska’s Mt Pavlof had an eruption that, at its peak, was spewing debris up to 7miles into the atmosphere. While the eruption did not last long enough to alter the climate, it did affect the regional temperatures and wind patterns. The next two cold fronts caught the debris and were quite chilly. The jetstream dipped much further south than it normally does.
History shows large Russian and Alaskan volcanoes typically shape a weather pattern that scientists a positive PNA (Pacific/North American). Our Browning World Climate Bulletin warned our clients on April 1 that the first two cold fronts that hit the Midwest and East would be dramatically cold. Indeed, parts of the Great Lakes and Northeast had more snow in April than they had had all winter! Now the fronts are past.
Hopefully you enjoyed the last taste of winter. Mt. Pavlof is quiet now and spring has returned bringing flowers, pollen and warm, sunny weather.
Remember the last Weather Whisper’s blog, which reported on Atmospheric Rivers, huge streams of moisture, thousands of miles long and only a couple of hundred miles wide, that flowed from the tropics towards the poles. California calls its “river” the Pineapple Express and Texas and the Midwest get rain from the Mayan Express. The Mayan Express hit last year in May/June and around Christmas. This year, it hit in March and is flowing again in mid-April. When it hits a cold front, like the storm in Colorado, it gets more energy and dumps even more water on the US. Remember, during springtime El Niños, like now, precipitation is frequently concentrated in these flooding rivers rather that frequent moderate rains and snows.
To the TSCRA – thank you for your wonderful hospitality at your convention this month. To those who asked about Evelyn’s health, I am doing well. I can’t do heavy travel anymore, but continue to write, research and grin as James now does all the standing in those long airport lines. – EBG | JJG