White Christmas still lookin' good

We’re less than two weeks from Christmas and conditions are still looking very good for snow here in Coeur d’Alene.

The long-range computer models have been consistently showing a northwesterly flow over the Inland Northwest, which increases the chances for snowfall across the region. The period in front of Christmas this year is the normally cooler and often wetter full moon lunar phase.

Last year, we had a white Christmas, but the snow started to fall later in the day. Prior to Dec. 25, high temperatures warmed into the 40s from Dec. 19 through 21, peaking with a high of 47 degrees on Dec. 20. There was also nearly a half-inch of rain that resulted in a complete melt-off of snow in the lower elevations.

However, this year’s weather pattern looks different. Temperatures over the next several weeks are expected to remain mostly in the 30s for much of the week with occasional snow and only a chance of some rain mixing in during the day.

In the waters of the south-central Pacific Ocean, we have an intensifying, cooler-than-normal sea-surface temperature pattern, La Nina. This phenomenon often leads to above-normal snowfalls across the Inland Northwest.

We also had a La Nina last year as Cliff had a total of nearly 17 inches of snow at his station for the season to date in mid-December. In 2021, there has been around 10-15 inches of snowfall in the region, but the overall trend is looking more favorable for snow later this month and into January.

EARTHQUAKE UPDATE

In other environmental news around the Northwest, beginning last Tuesday, a series of nearly 100 earthquakes were occurring about 200 to 250 miles west of Newport, Ore., in the Pacific Ocean.

According to the Pacific Northwest Seismic Network, most of the earthquakes have measured from a magnitude of 3.8 to as high as 5.8. This new swarm of earthquake activity has not been detected on land, but has certainly been gaining more attention.

The earthquakes have been occurring along an active fault line called the Blanco Fracture Zone. An article by CNN says that fault line is more active than the San Andreas Fault, producing more than 1,500 earthquakes that have measured higher than 4.0 since the 1970s.

Despite the increased activity, the chances for a major earthquake along the Pacific coast produced by this fault are very low. Scientists say the risk of tsunamis from this type of fault is also minimal and the earthquakes along these types of faults that come in bunches are relatively common.

This region of the Pacific Ocean has been very active. There was an eruption of the Axial Seamount volcano in April 2015, which is located in the eastern Pacific Ocean about 300 miles west of Astoria, Ore.

According to OPB News, scientists at Oregon State University are predicting a major eruption of this active volcano. Within the last 25 years, the volcano has erupted three times and scientists believe another eruption may occur by the mid-2020s. Their forecast is based upon an increase in the number of small earthquakes near the volcano.

The Pacific Northwest will eventually see another major earthquake along a different region called the Cascadia Subduction Zone. Major earthquakes in the Pacific Northwest are not very common, but scientists are concerned about a potential large event along the West Coast of Washington within the next 50 years.

Based on historical evidence, there was a huge megathrust earthquake on Jan. 26, 1700, that was known as the Cascadia earthquake. It happened across a 620-mile area along the Cascadia subduction zone from the middle of Vancouver Island in British Columbia southward along the Pacific Northwest coast down into northern California. The magnitude was estimated between 8.7 and 9.2. The devastating Alaskan earthquake in 1964, the second-largest recorded in history, was a 9.2.

The big quake in 1700 was believed to have generated a large tsunami that hit the coast of Japan. It may also have been linked to the Bonneville Slide. This was a major landslide that dammed the Columbia River near Cascade Locks in Oregon. Native Americans referred to it as the “Bridge of the Gods.” However, other investigations state that the landslide occurred around 1450 based on radiocarbon dating and dendrochronology (tree rings).

Geologic evidence shows that a major earthquake that would likely cause heavy damage to Seattle, Portland, Vancouver and other big cities along the Pacific Northwest coast, occurs approximately every 400 to 500 years. So, the chances of a major event within the next 30 are currently around 10 percent.

The swarm of earthquakes off the Oregon coast are about 200 miles west of the Cascadia Subduction Zone, the region of bigger concern. Whether the current series of earthquakes is related to that fault, the Axial Seamount volcano or other factors may not be fully understood, but the recent events have made for some interesting analysis and discussions with area geologists.

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Contact Randy Mann at randy@longrangeweather.com