A volcano in Alaska may erupt soon

A volcano near Anchorage, Alaska, called Mount Spurr, has been rumbling. As a result, the U.S. Geological Survey and Alaska Volcano Observatory issued an alert. This indicates that the volcano, which is located about 75 miles west of Anchorage, has an increasing chance of erupting within weeks or several months. Scientists at the Alaska Volcano Observatory say that if an eruption is about to occur, then they would “expect to see further increases in seismic activity, gas emissions and surface heating.”

Alaska is one of the regions that is notorious for earthquakes and volcanoes. The state holds the record for the second strongest earthquake recorded since 1900. On Good Friday, March 27, 1964, a massive 9.2 magnitude earthquake hit the south-central portion of the state, which devastated Anchorage and surrounding regions. According to the USGS, the state contains over 130 volcanoes and volcanic fields. Since 1760, over 50 have been active as it’s located within the infamous “Ring of Fire.”

About 90% of the world’s earthquakes and 75% of the world’s dormant and active volcanoes are in a region that stretches approximately 25,000 miles. This region, which looks like a horseshoe, extends from New Zealand, Indonesia, Japan, southern Alaska and along the U.S., Central American and South American West Coasts. The Pacific “Ring of Fire” is the result of the movement and collisions of the tectonic plates that have led to the creation of at least 750 active or dormant volcanoes, especially along the U.S. West Coast.

The newest concern is Mount Spurr, an 11,070-foot-tall volcano that is covered with snow and is classified as a “stratovolcano.” These types of volcanoes are often explosive when they erupt. They are usually the most pronounced as they have relatively steep sides and are cone shaped. Lava within these volcanoes is very sticky with high viscosity and does not flow very well, resulting in pressure build-ups. By contrast, shield volcanoes, like the ones on the Big Island of Hawaii, have broad and gently sloping shapes and the lava flows more freely as it has lower viscosity.

Mount Spurr has two main vents that have erupted over time. The vent in the main summit exploded more than 5,000 years ago. About 2 miles south of the summit is the Crater Peak vent. This one erupted in 1953 and on three occasions in 1992. According to the observatory, the next eruption is expected to be similar to the ones in 1953 and 1992.

The eruption of 1992 lasted for close to seven hours, and the explosion sent ash and dust as high as 50,000 feet into the air. Most of the ash was directed over the south-central portion of Alaska with a quarter of an inch of ash. There were reports that the ash cloud eventually traveled as far away as Greenland. Airline flights were canceled, and nearby Anchorage was plunged into darkness. Volcanic ash is typically very gritty, and scientists have been able to identify older eruptions as the material is composed of fine pieces of glass.

Assuming there is an eruption of Mount Spurr this year, there is a small chance that small segments of the ash cloud could drift into the Pacific Northwest. The upper-level winds would have to be from a northwesterly direction at the time of the explosion.

Of course, any ash from this volcano would not likely compare to the big eruption of Mount St. Helens back in May of 1980. About four hours after that eruption, ash moved over the Inland Northwest and day was quickly turned into night. Drifts of ashfall of up to several feet were reported throughout the region.

In terms of our local weather, the first two weeks of March were some of the driest in recorded history in the Spokane and Coeur d’Alene area. A storm system finally brought some much-needed rain and snow to the Inland Northwest. Despite the recent snowfall in the lower elevations, seasonal totals are about half of the seasonal normal of 69.8 inches in Coeur d’Alene.

With additional moisture expected over at least the next 10 days, we should get close to our seasonal norm. By the end of the month, Coeur d’Alene’s average precipitation to date is 7.77 inches. We’re now over 6 inches for the season but still below normal for March. Our average rain and melted snow total for this month is 1.94 inches.

At the Spokane International Airport, moisture totals are close to normal as over 0.8 inches have been reported. However, their seasonal total to date is approximately 4.50 inches as of the weekend. Snowfall at the airport is close to 29 inches for the season, compared to a normal total of approximately 43 inches.

The long-range computer models are continuing to show more moisture feeding into the western U.S. from the Pacific Ocean into at least early April. This would include Northern and Central California with a chance of additional moisture in Southern California, where that area has been experiencing flash floods and mudslides from the recent moderate to heavy rainfall.

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Contact Randy Mann at randy@longrangeweather.com.