One comment we've heard a fair amount is how windy it's been. And people aren't just talking about the windstorms of Jan 13th and Mar 28th. It just seems like there's wind every day. "Oh great, just what we need. More wind." So has it really been windier than normal? Does the data back up our perceptions? If so, what is the reason for it? And is this a trend we can expect to continue? OK, lots of questions, so let's see if we can provide some answers.
First, we have to start with a caveat, namely, that archives of wind data don't go back nearly as far as temperature records. Thermometers are fairly inexpensive and have been in widespread use for a long time. As such, temperature records in the Inland Northwest go back into the early 20th century, and at some locations (like Spokane or Lewiston), go all the way back to 1881. Unfortunately, wind anemometers (those spinning cups used to measure wind speed) are much newer to the scene of weather measurements, and generally they've only been found at airports. So wind records are much less plentiful both in location and time. Even so, we'll use what we have and try to draw some conclusions.
Has it been windier than normal this year?
To hopefully answer this question, we gathered all of the wind data we could find at a few different locations in the region. As with most data studies, there's a couple of ways to slice and dice the data. With wind, it really comes down to two types of measurements: the average wind over the entire day, and the peak wind gust of the day. They're obviously related to each other, but not the same. A thunderstorm can create a 50 mph gust on an otherwise calm day. Or a steady 25 mph wind can blow all day without ever gusting much over 30 mph. Which day is windier? So we'll try to look at both measurements to glean our answers.
First we'll start at Spokane, mainly because it has the longest data record. Peak wind gust observations for Spokane go back to 1969, while daily average wind speeds started in 1984.
We'll start by looking at the number of days each year where the wind gusted to 50 mph or more.
Looks like just about every year has 1 to 3 events with wind gusts over 50 mph. And 2020-21 was no different, with a total of 3 events. Notice, though, that there have been years with a few more windy days in Spokane. 2011-12 had 5 such days. And looking back much further, the winter/spring of 1970-71 had 6 days with 50 mph or more, and 1971-72 had a rather amazing 12 such days.
So let's bring it down a notch, and look at days with gusts of 40 mph or higher. (The orange line is average of the previous 5 years)
Now we start to see a slightly different pattern. 1971-72 still tops the list, but there are now several other years that had a lot of windy days (greater than 40 mph gust). 1988-89 as well as 1989-90 were rather windy years in Spokane. But then there seems to be a lull in the wind for Spokane for the 1990s and early 2000s. Since 2005 however, the windy days have returned. More recently, the >40mph days in 2020-21 totaled more than any year since 2013-2014. So from that standpoint, yes, 2020-21 was winder than recent years. But it certainly wasn't the windiest ever.
When we lower it down to 35 mph, things become a little more interesting.
Now, the really windy years of the early 1970s don't show up as well. In fact, the top winters are now the 1988-89, 2013-14, and our current 2020-21. So while some years may have a few really windy days (like 1971-72), they may not have many other windy days during the year. Meanwhile, other years may have a number of days over 35 or 40 mph, but few if any over 50 mph.
Peak gusts don't always give a good indication of a windy day. A thunderstorm or shower can cause a strong wind that lasts only an hour in an otherwise calm day. Average wind looks at all hours of the day and averages them. Below is the number of days in Spokane where the average wind speed was greater than 15 mph.
Similar to our results from looking at peak gusts, the 2020-21 as well as the 2019-20 years have been windier than any year since 2011-12. So yes, it has been windier in Spokane of late than for the past 10 years. Still, we see even windier years in the late 1980s as well as 1998-99. So it would be wrong to say that this past year is the windiest ever in Spokane, or even that there is a trend for windier years.
Let's expand our study a bit, and look at other locations in the Inland Northwest. The >40mph wind gust data from Pullman is interesting.
The number of days with gusts >40 mph at Pullman this past year (2020-21) was higher than all other years, with the exception of 2010-11. So for the folks in Pullman/Moscow, it was a noteworthy year for wind. Or was it? Here's the number of days with wind gusts >45 mph.
Now the past year doesn't look so windy compared with earlier years. What gives? This would suggest that yes, Pullman/Moscow had a large number of windy days (over 40 mph), but didn't necessarily have an unusual amount of very windy days (over 45 mph).
Further to the south in Lewiston, we see a similar signal as at Pullman. Here's the number of days with gusts >40 mph at Lewiston:
Still, this past winter was one of the windiest, but not the windiest year on record.
At Moses Lake, the story is a bit different. Here's the number of days each year with gusts >40 mph.
2019-20 is actually the clear winner for this category, with 2020-21 similar to several other years.
For average wind speed at Moses Lake, the past few years aren't really anything exceptional, especially when compared with the 1998/99 winter (a very wind La Nina winter) and the 2001/02 winter.
So in summary, in some respects, yes, it has been windier in the Inland NW recently than over the past 10 years. But it would be wrong to say that "it's never been this windy". Clearly the data shows that there have been windier years in the past.
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