Is Mount St. Helens showing new signs of life?

Over a week ago, the United States Geologic Survey (USGS) stated that a large number of small earthquakes were reported around Mount St. Helens. The swarm of tremors, over 130 of them, had magnitudes of 0.5 or less. The tremors have been increasing since March, but, they were so small and about 1 to 4 miles deep, no one could feel those small quakes even if they were standing directly on the surface directly above them.

There is a correlation between earthquakes and volcanic eruptions. When Mount St. Helens erupted on May 18, 1980, it began with a magnitude 5.1 earthquake preceded by thousands of smaller quakes. More than 1,000 feet was blown off from the top of the mountain that left a huge crater. The eruption was the deadliest and most expensive volcanic eruption in U.S. history. The event killed 57 people, led to a number of forest fires and widespread mudflows due to the melted snow from the mountain.

Prior to the big 1980 eruption, the USGS noticed a huge 450 foot bulge in the mountains northernmost flank. It was expanding at a rate of 6.5 feet per day and volcanologists soon realized that an eruption was imminent.

Despite the recent increase in earthquake activity, scientists at the USGS don’t anticipate a new eruption anytime soon. The new round of earthquake swarms around Mount St. Helens is not new. In the late 1990s, there were more energetic swarms with another series occurring in 2013 and in 2014.

There’s no question that the volcano is still very active as volcanologists believe that the magma chambers are slowly recharging. As I mentioned in an article last month, Mount St. Helens and other volcanoes like Mt. Rainier, Mt. Hood and others, lie within a region of high earthquake and volcanic activity that stretches approximately 25,000 miles called the “Ring of Fire.” This area that looks like a horseshoe which 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 over 450 volcanoes, especially along the U.S. West Coast.

At least several years after the eruption, I remember taking a trip to Seattle. While on the plane, the pilot would tell everyone in the cabin that he was taking the plane very close to Mount St. Helens. Many passengers would actually jump from their seats and go to the side of the aircraft to get the best view. I thought it was kind of cool at the time, but I don’t believe we would see a repeat of passengers all jumping to one side of the plane for a photo opportunity of Mount St. Helens or any other feature.

In terms of our local weather, the beginning of last week started off cool and wet. A chilly storm from the north did bring some snow to the higher mountains of North Idaho. Cliff even saw a few flakes of snow mixing in with the rain early Monday, May 9. Except for some leftover showers on Tuesday, the rest of the week was pleasant with afternoon highs climbing into the 70s.

However, as we get closer to the ‘full moon’ lunar cycle of May 21-28, Cliff and I do see more showers and thunderstorms across North Idaho and the rest of the Inland Empire.

In late May and early June, which includes Memorial Day, we should dry out and warm up. But, there may be a few showers over the mountains at times. Temperatures will likely climb into the 70s and into the 80s across the region. There’s even a chance we could get close to the 90-degree mark.

Then, around the June 4-11 ‘full moon’ cycle, there’s an increasing probability of more showers and scattered thunderstorms. We’ve been talking about this big high pressure ridge that has been situated over the western states. There are indications that this system will be slowly moving to the east later in June and July. The hot and dry weather is forecast to end up in the central U.S. Assuming this pattern develops, our summer season should not be as hot or as dry as the one in 2015.

Despite a cooler and slightly wetter summer season, there should be plenty of afternoons with highs warming into the 80s and 90s. And, don’t be too surprised to see at least one afternoon with highs around 100 degrees. Stay tuned.

Contact Randy Mann at randy@longrangeweather.com