Tuesday, May 06, 2025
63.0°F

More on supervolcanoes ... but not to worry

by Randy Mann
| July 11, 2016 9:00 PM

Last week, I featured an article discussing Yellowstone’s eruption history. Apparently, there are a number of people who are extremely concerned that a major eruption of this supervolcano may be seen in the near future.

I’m telling everyone to not lose sleep over Yellowstone. The chances are extremely small for any kind of eruption within our lifetime, our children’s lifetime and at least their children’s lifetime. I’m sure there will be those who disagree, but scientists are fairly certain that no major eruption is on the horizon at Yellowstone.

The Yellowstone Caldera, also known as the Yellowstone Supervolcano, is located primarily in northwestern Wyoming and measures a rather big 34 by 45 miles. The park lies over a hotspot of light, hot and molten rock deep from within the Earth. Over millions of years, thanks to tectonic activity, the North American Plate we live on has been slowly moving to the west-southwest. Therefore, there have been many older calderas from previous eruptions discovered relating to this hotspot stretching across southern Idaho and as far west as the Nevada and Oregon border.

Scientists believe that there could have been as many as 50 large eruptions over millions of years. Some of these explosions have helped to create the eastern portions of the Snake River Plain across southern Idaho. One caldera in the southern portion of our state, the Bruneau-Jarbidge caldera, was believed to be formed from an eruption around 10 to 12 million years ago and dropped volcanic ash up to a foot deep as far away as northeastern Nebraska.

In what is now the Ashfall Fossil Bed State Historical Park in Nebraska, fossils of animals that are now more native to Africa such a rhinoceros, camels, mammals and others, were found mixed in with the volcanic ash. Fossil evidence shows that many of those animals died of lung failure due to inhaling of volcanic ash from an eruption of a supervolcano, the same one now below Yellowstone, about 1,000 miles away.

By the way, volcanic ash is easy to spot. If you put some of this ash under a microscope, it would sparkle as volcanic ash is made up of fragments of pulverized rock, minerals and also fine pieces of glass.

When discussing the topic of supervolcanoes, most of us think of Yellowstone. But, there are other supervolcanoes across the globe that have erupted in the past. For example, there is the Long Valley caldera located in east-central California that is just south of Mono Lake near the Nevada state line. The last time there was an explosion in this region was about 760,000 years ago with ash reaching as far east as Nebraska. This area is still active as there was a swarm of large earthquakes and a 10-inch rise of 100 square miles of this caldera in 1980.

About 74,000 years ago, another supervolcano exploded in North Sumatra in Indonesia. Evidence suggests a big cold period followed this eruption and may have dwindled the human population in Africa from hundreds of thousands to just a few thousand. Another supervolcano is located in New Mexico which erupted around 1.5 million years ago. New Zealand had a big eruption about 26,000 years ago and smaller one in 181 A.D. Southern Japan, Argentina, Chile and Bolivia are other parts of the world with supervolcanoes that have likely seen big eruptions in the distant past.

So what does this mean? Well, it means that our Earth is constantly moving and changing. Again, I wouldn’t be too concerned of a major eruption anytime soon.

•••

In terms of our local weather, despite a drier than normal spring and early summer season, moisture totals for Coeur d’Alene are still above average, more than an inch-and-a-half as of late last week, for the 2016 season. Showers returned to our region last Friday, and except for some scattered mountain showers, it does look like we’ll have a dry and warm weather pattern for at least the next 10 days.

There is a chance of some showers and a few thunderstorms toward the end of this month. The early to mid August period still has an increasing chance of showers, assuming the big ridge of high pressure in the West moves eastward into the center of the country.

Despite the upcoming warmer weather, temperatures for the rest of the summer of 2016 should be close to normal. Last summer, in 2015, Cliff recorded 16 days in a row with temperatures at or above 90 degrees. That heat wave began on June 25 and continued through July 10. June 28 of 2015 was very hot with a sizzling 105 degrees. Cliff and I don’t see a stretch of that type of hot weather this year, but there will be some additional 90-degree days before the summer season comes to an end.

The 2016 edition of the North Idaho State Fair looks pretty good weatherwise, but there could be some showers around toward the beginning of this event. Stay tuned.

Contact Randy Mann at randy@longrangeweather.com