The Puget Sound Convergence Zone Delivers and Well-Timed Precipitation and Smart Water Manegament Keep Yakima Crops Yields High

Before I get into the Yakima Valley situation, let me note yesterday's substantial precipitation over central Puget Sound from a decent Puget Sound Convergence Zone.

Remember, Puget Sound Convergence Zones often occur after the passage of a Pacific front, when air approaching the coast turns to the west and northwest (see schematic below).  

Air moves around the Olympics and then converges over central Puget Sound, producing upward motion, clouds, and precipitation.

A very well-defined convergence zone formed yesterday afternoon, as illustrated by the radar image around 3:30 PM.

The precipitation totals for the past days show a nice band of precipitation around the central Sound, with particularly heavy rain in the mountains (reaching 2 inches!).   

Very good for Seattle's reservoirs,  which got a large hit of rain yesterday.

The Spada Lake reservoir, which supplies the North Sound area, is filled to above normal now.

Another interesting precipitation story has been the Yakima Valley.    

After all the angst in the media about drought and low snowpack, there was sufficient water for Yakima agriculture, with all important crops of good quality and with near-normal harvests.

How cold this be with a low snowpack?   

Annual precipitation was near normal due to heavy winter precipitation, so reservoirs were filled to normal or above normal levels.    The summer was not particularly hot.

And then there was was divine intervention

There was substantial precipitation over the Yakima Basin during the summer and autumn (see below).  

Just stunning.   

With substantial precipitation,  all water limitations have been removed in the Yakima Valley.  Both senior and junior rights folks can receive their full water allotment!

Sometimes when meteorologists pray to the weather gods, our supplications are answered.  

Seattle Times Story on Skagit Flooding and Global Warming is Clearly Wrong

 It happens again and again.

The Seattle Times Climate Lab runs a story claiming global warming will create a dangerous situation.

A story that is factually incorrect or grossly exaggerated.

And it happened again yesterday in a Seattle Times story about Skagit Valley flooding:

This article claims that global warming will cause serious flooding of the Skagit River.   This is clearly wrong.

Specifically:

• The article is based on a report by an advocacy group.  A report that has serious technical flaws.
• The Seattle Times provides no analysis of the claims' viability, nor does it examine historical data to determine whether such an ominous trend is occurring.
• The report claims that "today’s 100-year flood events, or those considered to have a 1% chance of happening in any given year, will happen about four to five times as often by the 2040s. 

The Seattle Times suggests that existing infrastructure will not protect communities.   Disaster looms due to climate change.

Written by the Climate Lab project of the Seattle Times, it is an unfortunate example of "sponsored journalism" paid for by local advocacy groups. 

The article is based on a report led by the Swinomish Indian Tribal Community, which has secured tens of millions of dollars of funding from state and federal sources for adaptation to global warming.   

There are serious technical flaws in this report and the ST articles.   

For example, the climate models considered are driven by unrealistic increases in warming greenhouse gases, such as CO2.   

Specifically, they make use of an average of the RCP 4.5 and 8.5 climate change scenarios. Unfortunately, RCP 8.5 is considered wildly excessive, so much so that the Intergovernmental Panel on Climate Change (IPCC) has dropped it.

The report and the Seattle Times failed to examine the actual historical trends of the high water on the Skagit River, which is important since global warming has occurred for several decades.

Let me show you the actual data.    Below are the OBSERVED long-term trends of the annual peak streamflows of the Skagit River at Nehalem and Concrete.  It is not rising, but DECLINING slightly.   

Please note that peak streamflows were higher earlier in the century, before the reservoirs were in place.

No wonder they failed to show past observations.  It does not support their narrative. 

What about the future under global warming?  

The UW effort to run high-resolution climate models driven by the more reasonable RCP 4.5 scenario (blue line) shows little increase in precipitation in the Cascades through 2080 during the winter at any site (Stampede Pass is shown below).  

While the article makes big claims about climate change for Skagit flooding, it conveniently avoids other issues, such as land use changes.   

For example, dike and levee construction has resulted in increased river confinement. By walling off roughly 100,000 acres of the natural floodplain, the river lost its ability to naturally spread out and slow down. Instead, the water is funneled into a highly confined channel, forcing the river stage to rise much higher and faster at narrow points like downtown Mount Vernon. 

Urbanization and increased impervious surfaces have also been a factor

The growth of urban centers along the river, such as Mount Vernon, Burlington, and Sedro-Woolley, has converted porous, forested, and rural land into asphalt, concrete, and roof surfaces. 

Thus, when heavy rain or atmospheric rivers strike the basin, the water is impeded from soaking into the ground. Instead, it turns into rapid urban runoff that empties directly into local tributaries and the main stem of the Skagit River, causing rapid spikes in water levels. 

Deforestation and logjam removal

The removal of upper-basin forest cover and natural river obstructions permanently increased the velocity and volume of water and sediment rushing downstream toward Mount Vernon during major storm events. 

Reduced snowpack as a cause?

Finally, both this article and report claim that reduced snowpack is an important element in Cascade flooding.   They say this because global warming clearly reduces Cascade snowpack.

But they got it wrong.   

Severe flooding in western WA is always associated with intense, warm atmospheric rivers in which nearly all the precipitation falls as rain.  Furthermore, the melting of snow is always secondary for western Washington flooding.   

In short, this kind of  "supported" journalism at the Seattle Times is not meant to inform but to push a certain agenda

Really unfortunate.