Drought Update

With recent drought declarations over portions of Washington State, we will take a look at the latest drought situation and conclude with a brief update on the fire season outlook.

Let's begin with the US Drought Monitor depiction as of June 4th, 2019.

US Drought Monitor - June 4th, 2019

As you can see, most of the country is free of drought with a few exceptions.  One of those is across portions of Washington and the Idaho Panhandle.  This product is updated every Thursday.  The latest version can be found here

This is a major change compared to last year!  Here is what the situation looked like one year ago where drought  covered much of the southwest and portions of eastern Oregon.

US Drought Monitor - June 5th, 2018

Now let's take a look at our current situation, beginning with a zoomed in look at our region.

US Drought Monitor - June 4th, 2019

Moderate drought conditions exists along the East Slopes of the Cascades, as well as up around Northport, Metaline Falls, Bonners Ferry, and Sandpoint.  Abnormally dry conditions are noted by the yellow shading on the map.  Severe (D2) drought is noted over parts of Western Washington.

When looking at drought, we often analyze both short and long term conditions.  We will begin with the month of May which was 2-4 degrees warmer than normal for most locations.

And now May precipitation

May brought some much needed precipitation over Okanogan and Chelan counties where moderate drought conditions exists.  May was much drier than normal over extreme NE Washington and the north Idaho Panhandle. 

The warm May resulted in snow melting off a few weeks early in the mountains.  Here is Schweitzer Basin SNOTEL near Sandpoint, ID

Schweitzer Basin SNOTEL - Snow Water Equivalent (SWE) 

The black line is this year while the dark green line represents a normal melt off.  And here is Harts Pass located high up at 6500 feet along the Cascade crest northwest of Mazama, WA

Harts Pass SNOTEL - Snow Water Equivalent (SWE)

Now let's look at some longer term conditions beginning with percent of normal precipitation October through May.

Precipitation since Oct 1st has been below normal over western Washington, and most of northern Washington into the Idaho Panhandle.

There are several drought indicators that are analyzed.  One of them is the Palmer Drought Severity Index (PDSI).  This looks at long term precipitation and temperature data to access drought conditions.  Yellow, orange, and red colors side towards drought conditions.

Another indicator is stream flow.  Here is the latest 7 day stream flow compared to historic stream flow for Washington and Idaho for June 10th, 2019.

Below to much below normal values currently in the same drought depicted areas.  And finally here the summer stream flow forecast

The dots are small, but a close eye can see the orange colors around Chelan, Omak, and Sandpoint which indicates 50-75% of normal water supply this summer.  Southeast Washington is looking much better.

Drought conditions have led to below normal soil moisture over portions of northern Washington.  This could make the grass and timber more susceptible to fire starts this summer.   But how many fires and number of acres burned will depend on how many critical fire weather patterns set up as mentioned in previous blog post here

Here are the latest fire outlooks from NIFC issued June 1st. 

These update on the 1st of each month and can be found here.  The key word in this outlook is potential.  The potential exists for an above normal fire season in northern Washington into the north Idaho Panhandle, but doesn't guarantee one.  We will continue to monitor the drought and fire situation as we go through the summer.