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Powerful Pacific System Impacting the West; First Significant Snow for Portions of the East

Power Pacific system will continue to bring significant impacts for Pacific Northwest into northern California the remainder of the week. Dangerous coastal affects, heavy rain, flooding, strong winds, and higher elevation mountain snow continues. Meanwhile, a storm across the east is set to bring the first accumulating snow to many higher elevations of the Catskills into the central Appalachians. Read More >

We’ve had a lot of interest in the wind this year, specifically on putting how strong it’s been in perspective, or to validate the feeling that this must be some kind of record. It’s a tough question to answer, and took a deeper dive to find some answers. 

You’ve probably never heard us talk about wind in terms of records before, like we do temperature and precipitation, and there’s a reason for that. At present, the National Weather Service utilizes the Automated Surface Observing System (ASOS) for official weather observations across the country. These weather stations, nearly 1000 of them, observe continuously and routinely report back automatically and objectively. This national standard began in the mid to late 90s. Before that time, manual observations were the norm on much less frequent time scales and with some element of subjectivity. All this to say, we're not truly comparing apples to apples with wind data prior to the ASOS era with that of the ASOS era. 

So what can we say about the wind so far this year? It was likely the windiest April, and start to the year through April 30th for that matter, on record across the area since *at least* the mid to late 1990s based on average wind speed. Let's look at the data. Below are national maps from the National Center for Environmental Information (NCEI) that show the average wind speed (left) and departures from normal (right) for each month so far in 2022. 

 

As you can see, we can confirm that it's been windy, and above average. But most of us already knew that! Also note that "average wind speed" is what's being reported here - that is the best way to compare over longer time periods of data and is therefore the best way to provide perspective. Wind roses are another great tool to show what the average wind has been at specific locations, and provide additional information on the direction of the wind as well. Wind roses can be found at the SD Mesonet from SDSU and from the Iowa Environmental Mesonet website. Below are examples for Aberdeen. On the left is a plot of what the wind speed and direction normally looks like through the month of April, whereas the plot on right is what April 2022 looked like. The main thing to notice is how much larger a percentage of time we had 20+ mph winds this April (maroon color, and out of the northwest) vs normal (brown color). Notice too on this April's plot how the average wind was 16.6 mph and we were calm only 1% of the time!

 

Now that we know what our average wind speed is for each month at specific locations, we can make plots to compare different periods over time. The plots below are from the Iowa Environmental Mesonet (IEM), first showing how just this April compares to previous Aprils for Aberdeen, Watertown, Pierre, Mobridge and Sisseton, and then how the whole year of 2022 (January 1 - April 30) compares to previous years for the same sites. Again, we have to look at this data with some knowledge about how observations have changed over time. From Daryl Herzmann, who runs the IEM website and creates these charts and many others across the country: “Unlike temperatures, which are a bit more straight forward to measure and have long term and reliable records, the archive of wind information is problematic, to say the least. Documented and some undocumented changes in observation techniques, recording heights and reporting intervals make long term comparisons very tricky.” When using Des Moines as an example in one of these charts for April, he says, “Well, you can see the dominance of higher values during the first 30 years of the period of record, which pull the long term average up. Was it really windier back then or is this a result of changes in observation? Sadly, it is difficult to say…”

April 2022 average wind compared to past Aprils

 

What was responsible for the wind this April? Several large and deep low pressure systems tracked across the Northern Plains. Specifically:

  • April 5-7th: A strengthening area of low pressure over Minnesota brought high winds to central, north-central, and northeastern South Dakota from the afternoon hours on Tuesday, April 5th, through the evening hours on April 7th. Some of the highest wind gusts include 65 mph at the Pierre Regional Airport and 17 miles west of Polo, and 64 mph 13 miles north of Vivian. The long-duration wind event caused sporadic tree damage and shingles to blow off of roofs, as well as the tipping of high-profile vehicles. Light, accumulating snowfall combined with the very strong winds to produce periods of reduced visibility over northeastern South Dakota as well.
  • April 12-14th: A powerful low-pressure system brought high winds from April 12th to April 14th across the area. Some of the highest wind gusts include 73 mph 11 miles south of Bullhead, 72 mph in Tunerville, 71 mph 6 SSW of Peever, and 67 mph 2 miles north of the Pierre Airport and 10 miles SW of Long Lake. The prolonged period of high winds caused sporadic tree and shingle damage to roofs, and tipped high-profile vehicles. In addition, the combination of ongoing drought conditions and the high winds caused blowing dust with significantly reduced visibilities at times in south-central South Dakota, as well as the spreading of wildfires. The combination of heavy snowfall and high winds produced blizzard conditions in Corson and Dewey counties, which caused the death of newborn livestock. Despite lighter snow amounts, blizzard conditions were reported across portions of the Prairie Coteau as well, leading to significant travel impacts and school cancellations. 
  • April 22-23rd: A powerful low-pressure system produced high winds across the area from the 22nd into the 23rd. Some of the highest wind reports include 79 mph at Herreid, 75 mph 5 miles east of Danforth, 69 mph at Webster, and 4 miles southwest of Mound City. Severe storms developed over south-central South Dakota during the evening hours of the 22nd and advanced northward into north-central and northeastern South Dakota into the early morning hours of the 23rd, bringing widespread damage to the area from hail up to two inches in diameter and 60 to 75 mph straight-line winds. Lightning caused some prairie and hay bale fires across portions of central SD as well. The center of the low-pressure system passed over Aberdeen on April 23rd at 12:20 AM CST, producing a mean sea level pressure of 983.5mb. The pressure was just 3.5mb shy of Aberdeen's 980mb record for April. A brief tornado developed during the afternoon of the 23rd in Edmunds County. Freezing rain in north-central South Dakota on the 23rd caused ice to accumulate on power lines. With ice accretion and high winds, many power lines went down, mainly in Corson and Dewey county. This storm system was the third significant storm system of April, which further delayed the agricultural planting season.
KELO Webcam showing the storm moving into Miller, SD Tree uprooted in Miller, SD - Photo from KCCR Radio Tree damage in Miller, SD - Photo from KCCR Radio
MODIS visible satellite imagery from April 5th, 6th and 7th MODIS visible satellite imagery from April 12th, 13th and 14th MODIS visible satellite imagery from April 22nd, 23rd and 24th

 

 

Looking back to the start of the year now: January 1 - April 30, 2022 average wind compared to the same time period of past years

 

Bigger picture: La Nina has been in place all winter, and a classic La Nina pattern such as we've experienced features a jet stream, and thus active storm track, across the Northern Plains. We were indeed impacted by many clipper low pressure systems, which led to numerous bouts of snow and cold air particularly across North Dakota as well as repeated episodes of strong wind across the whole region. In fact, the Grand Forks, ND area had recorded more blizzards (11) this winter season already by February 23rd than any other on record since at least the 1979-1980 season, surpassing the previous record set in 2013-2014 and 1996-1997 (10). This spring, an active storm track continued, and included several deep Colorado Low pressure systems across the region as well, particularly in April. 

La Nina is forecast to continue into the summer - find much more information about that here.