January 19, 2022 | View PDF
In the southwest Pacific Ocean, the Hunga Tonga volcano erupted on Saturday.
This ordinarily wouldn’t be a big news story because the same volcano erupted in 2009, 2014 and has been rumbling since December of last year. But Saturday’s eruption was far more powerful than those previously observed, and it triggered both a tsunami and a noise that were experienced thousands of miles away.
I like volcanoes. They give humans a healthy dose of humility. The power of a single major eruption, and the way it can impact the entire planet, reminds us there are forces at work on Earth that far exceed anything humans can produce. Just consider some facts about Tonga’s eruption on Saturday.
Tonga’s ash cloud punched right through the troposphere, the lowest layer of the atmosphere where we live and most weather takes place, and rose all the way up to 100,000 feet – nearly twice as high as a severe thunderstorm.
As it was doing so, atmospheric sensors programmed to detect lightning strikes registered nearly 70 lightning strikes PER SECOND within the ash plume. At one point approximately 60,000 lightning strikes were recorded in just 15 minutes.
The sound of the explosion was heard more than 5,000 miles away. National Weather Service offices in Alaska at Anchorage and Fairbanks confirmed reports of booming sounds that corresponded with the time of the eruption. This is not unusual when major eruptions occur. When Krakatoa erupted east of Java in 1883, the explosion was so loud that its sound waves actually circled the entire planet.
I was working in the weather center at WCCO-TV in Minneapolis on May 18, 1980 when Mount St. Helens erupted in Washington. We’d just acquired one of the first satellite picture animation computers ever used on TV weathercasts and were awed by images showing ash from that eruption spreading across America.
I remember scientists a few weeks later stating that Mount St. Helens, during the first day of that major eruption, spewed more sulfur dioxide into the atmosphere in 24 hours than all of American industry had in the previous 100 years. It irritates climate extremists when you point out that, even if the world stopped using fossil fuels tomorrow, one or two big volcanic eruptions would make such effort and sacrifice meaningless.
All that ash in the air also impacts global weather. Fine ash particles reflect sunlight, cooling atmospheric temperatures. It’s been calculated Krakatoa’s eruption lowered temperatures in the Northern Hemisphere the following winter by 0.72°F. That may not seem like much, but it did have an impact. And the effect persisted until the ash and sulfur dioxide were “washed” out of the atmosphere by rain – acid rain.
Saturday’s eruption also produced a tsunami. Wave levels on the coast of California ranged from 2-4 ft. above normal as the tsunami hit. King Cove, Alaska, registered a 2.7 ft. tsunami wave.
While the impacts on American shores were minimal this time, those anomalies show us tsunami waves can travel thousands of miles.As humans, we’d like to think we’re in control of the planet’s destiny. Volcanic eruptions, such as Saturday’s remind us we are not.