Monday, May 12, 2014

Eastern Washington Fields are Blowing Away

On Saturday I was biking around the hills near Vantage, Washington with some friends, and driving home in the early evening I observed a distressing sight:  the wind was literally blowing away several freshly plowed fields, with plumes of dust extending hundreds of feet into the air and long distances downwind (see picture).

Clearly, some farmers are not being good stewards of the land entrusted to them.

The view Saturday evening around 6:30 PM from I90 near Ellensburg.

 Spring is often a dusty period in eastern Washington for two reasons:
  • it is a time when some farmers plow their fields in preparation for planting
  • strong winds return during this time of the year, particularly over the eastern portion of the region
To illustrate the later, here are the monthly average winds at Ellensburg and some other Washington locations.  You will notice the huge monthly variations of winds at Ellensburg along the eastern slopes of the Cascades, with the strongest winds in spring and summer.

Why are the strongest winds over the eastern side of the Columbia Basin strongest during the warm season?  Why aren't winds the strongest during the winter storm part of the year?

As illustrated in the following surface chart for July 16, 2013, high pressure builds over the eastern Pacific during the summer, while pressure falls over the heated land.  The produces a fairly strong onshore pressure difference that is accentuated by the cool air over western Washington and the warmth of the Columbia Basin.  Air accelerates eastward in the Columbia Gorge and down gaps and canyon of the eastern Cascade foothills..

The bigger the temperature difference between east and west, the larger the pressure difference and thus the stronger the winds.

Interestingly, our global climate models suggest that global warming could make these winds stronger!  Why?  Because the warming continent will have lower pressure than today and the Pacific High will strengthen.   More pressure difference and thus stronger winds.   That implies more wind energy in 50 years...and yes, more dust.

The summer winds at Ellensburg and vicinity tend to be strongest in later afternoon and early evening after the daily heating has revved up the pressure gradient during the day.  That is why the dust storm was apparent during the late afternoon but was absent in the morning.

Warm-season dust storms in eastern Washington can also be caused by strong outflow from thunderstorms or powerful winds from cold fronts moving down from British Columbia.

Blowing dust from eastern Washington farms during the spring can often be clearly seen in weather satellite imagery, such as this picture from the MODIS satellite in May 3 2010.  You can see the dust being pulled off the fields near the Columbia River and then heading towards the east.


Dust storms from thunderstorms often look very ominous and are called haboobs.  Below is a picture of one last September that was described in an earlier blog.

Picture courtesy of KauaiGuy808 on Flickr.

So how much soil is being lost from eastern Washington farms?   A study by WSU found that six high-wind events occurred over a two year period, with soil loss ranging from 43 kilograms per hectare (100 by 100 meters) during the 12-22 September 2003 event to 2320 kg (2.5 tons) per hectare on 27–29 October 2003.  So this is a significant loss.

I am no agricultural expert but surely they must be better agricultural practices that would lessen the dust storms from plowed fields, something I have seen many times on my visits to eastern Washington.




10 comments:

Random Menace said...

Farther east, in the Palouse, no-till agriculture was developed to preserve topsoil in the steeply rolling hills surrounding WSU: No-Till: the Quiet Revolution.

Unknown said...

That soil can't just vanish into nothing. Where does it come down? Isn't that place the lucky recipient of fertile soil?

Michael DeMarco said...

That soil is there because it was wind deposited and it will leave the same way with a strong assist from industrial faming methods that are driven by short term bottom-line concerns.

B. E. Ward said...

No-till is a good start, but I think the ultimate culprit is our system of annual-based industrial monoculture. Nature doesn't have thousands of acres of one plant, so why do we? If those fields had a balance of trees, grazing grasses, and annual food crops, there likely wouldn't be nearly the topsoil depletion.

Jason the Son #1 said...

You would probably be interested in uw professor Montgomery's book, Dirt. Walk over and ask Dave for a copy!

Chris Wright said...

No tillage or reduced tillage farming practices not only reduce windblown soil erosion, but also water erosion, promote better soil health and biological activity, and reduce fuel consumption, amongst others.

Dan said...

I was caught in one of those May 3 dust storms about 20 miles north of Moses Lake at 0930. It is not fun to drive through (or safe) and can't imagine having to deal with it while on a bike.

Over the last week I've driven about 500 miles through eastern WA, primarily on unpaved rural roads. There's a LOT of soil moving around in the air out there.

Stuart McDowall said...

Hi Cliff, I'm was a farm boy in the Quincy Valley near George. Or, more accurately, ground zero for that satellite shot of a typical spring dust storm. Afternoons riding the bus back to the farm were an adventure in white-out conditions every spring.

The 'soil' in the Columbia Basin isn't the precious stuff we know from the Midwest. It's Sandy Loam -- with the emphasis on SANDY. The sand has barely enough clay to hold water and fertilizer long enough to support plant life. It's a classic desert there in the Cascade Rain Shadow without the federal Irrigation Project bringing water down from Grand Coulee Dam.

The Irrigation Project doesn't release water down to the desert until about April (it varies)...but the farmers need to get their seeds in the ground in March because we don't have a super long growing season up here in the northern latitudes. And when they till--they stir up the dry sand...add some winds howling down that channel from Snoqualmie into the Basin and that's how the dust storms start.

But don't worry about 'soil' management...whatever soil this area had was washed away by the Missoula Floods. It's just sand now. Sand soaked in pesticide and fertilizer with a dash of Mt. St. Helens ash. They should just rename George "Claritin."

jeff said...

The wind arrives before the irrigation water. Remember it takes time for seeds to germinate and grow to create ground cover. The wind in the area described commonly reaches 30mph for days and days. The soil begins to move at 18 mph. Whats a Farmer to do?

Stuart McDowall said...

I forgot to mention...why don't they bring the water down from Grand Coulee earlier?

A. The overnight lows are still below freezing in March in the Columbia Basin.

B. The irrigation water comes from.....wait for it....the mountains! Snow in BC has to melt, make its way to the Columbia, then wind its way down the network of canals. It takes a while. And I'm leaving out the Bonneville Power Administration's mandate to use reservoirs to meet electricity demand.