There was another big volcanic eruption earlier this month

As reported in previous articles, there are over 1,500 active volcanoes around the Earth with an average of 50-70 eruptions per year. According to VolcanoDiscovery.com, as of the weekend, there are over 40 volcanoes that are currently erupting. Active volcanoes have occasionally wrecked airline travel plans. Mostly recently, another eruption in Indonesia resulted in flight delays and cancellations.

The volcano that erupted in early September was Anak Krakatau. It exploded for more than 24 hours and shut down eight airports as an ash cloud was sent about 50,000 feet into the atmosphere. The latest data shows that the ash and gas emitted from the volcano stayed in the lowest layer of our atmosphere, the troposphere, and is not expected to have an impact on the cooling of the Earth’s temperature.

Volcanic ash is primarily a mixture of rocks, minerals, and tiny glass particles. These particles are specific enough to give geologists a history of previous eruptions. The composition of volcanic ash makes it extremely abrasive. Airlines will avoid them as they can permanently damage the windscreens pilots use to see out of the plane. The ash clouds can also clog or damage sensitive sensors and have a major impact on the airplane’s engines.

This region of Indonesia is highly active for volcanic activity. Anak Krakatau was previously named Krakatoa. That volcano was famous for a series of 4 enormous explosions that occurred Aug. 26-27, 1883. The third eruption of the series was the loudest volcanic explosion that has ever been heard on Earth. It was so intense that sailors on ships that were within approximately 40 miles went permanently dead from the shockwaves of the huge eruption.

As the loudest sound in human history, the eruption was heard over 3,000 miles away. Scientists estimate that the blast had reached 172 decibels. By comparison, the decibel record at the Seattle Seahawks stadium reached 137.6 decibels. Also, 150 decibels are enough to rupture human eardrums. The sound waves from the eruption circled the Earth seven times. They were recorded on barometers as pressure spikes.

One of the main causes of the Krakatau and Anak Krakatau eruptions was the movement of magma beneath Krakatau. Indonesia lies along the boundary of several tectonic plates, where the Indo-Australian Plate is being forced beneath the Eurasian/Sunda Plate. This subduction process generates magma deep beneath the Earth's surface. As magma accumulated beneath Krakatau over the years, pressure increased within the volcanic system. Eventually, magma and volcanic gases forced their way toward the surface and led to the explosions.

Although this latest eruption in Indonesia was not big enough to have an effect on the Earth’s temperature, there have been eruptions in recent history did lower our planet's temperature. The most recent was Mount Pinatubo in 1991. This eruption in the Philippines sent 15 to 20 million tonnes of sulfur dioxide and other materials into the stratosphere. Global average temperatures fell about a degree Fahrenheit for 1-2 years.

In 1883, Krakatau injected tens of millions of tons of sulfur gasses and dropped the global average temperature about a degree Fahrenheit.

The explosion from Mount Tambora in 1815 was one of the largest explosions in modern times and the Earth’s temperature dropped by about 1.5 degrees Fahrenheit. However, over land areas it’s estimated that readings cooled by an average of 2-3 degrees Fahrenheit resulting in a “Year Without a Summer” in 1816. An eruption of a Mayon volcano in the Philippines in 1814 may have also contributed to Earth’s cooling.

According to the US Geological Survey, a major volcanic eruption, one big enough to send sulfur gas into the stratosphere, can temporarily lower our planet’s temperature by around 1-2 degrees Fahrenheit for 1-3 years. However, scientists are unable to predict exactly when the next big eruption will occur. A major eruption from a supervolcano, such as the Yellowstone caldera, could cool the planet for decades and drop the Earth’s temperature at least 5 degrees. The next eruption from Yellowstone is not expected for at least tens or hundreds of thousands of years.

In terms of our local weather, September’s precipitation total will end up above the 1.48 average. At Cliff Harris’s station in Coeur d’Alene, 2.20 inches of rain has fallen thus far. Showers are possible across the region at the end of the week with the long-range computer models indicating the possibility of more rain by Oct. 1. In fact, the pattern of above normal moisture across the Inland Northwest may persist well into next month. If this pattern persists, it would certainly be good news for the region’s drought situation.

As mentioned earlier, the El Nino in the Equatorial regions continues to strengthen. Many forecasters are still predicting warmer than average winter season, which would translate into less snowfall. This is often the case with El Ninos, especially strong ones, but we’re seeing more extreme weather patterns, so anything is possible.

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Contact Randy Mann at [email protected].