Western US Drought Part 3: Wildfires

This is the final blog post in the 3 part series on Western US Drought. The previous 2 posts were about the current drought outlook and some of the effects of drought. This post will discuss the drought's impact on wildfire season.

A satellite image from September 5, 2020 shows 5 major fires burning in California. These fires were large enough to form pyrocumulonimbus clouds (thunderstorm clouds made by heat from wildfires).

One of the biggest impacts of drought is increased wildfires. The North Carolina Climate Office describes it this way: "If the dry conditions persist, a drought can develop, leading to conditions favorable for wildfires as all the excess dried-out vegetation provides ample fuel for the fires. ... Wildfires will ignite very easily under such dry conditions and can spread quickly." 

Drought has exacerbated recent fire seasons, with fires getting bigger, longer, and fire season in general expanding and having longer boundaries. 

The Environmental Defense Fund writes: "Not only is the average wildfire season three and a half months longer than it was a few decades back, but the number of annual large fires in the West has tripled — burning twice as many acres."

Below is a graphic of the numbers of acres burned in the Western US in recent fire seasons. (This runs through the middle of the 2020 fire season).

Graphic found here.

Notice a clear upward trend in acres burned, with some years having less, but an overall trend of more and more scorched acres. By the end of the 2020 fire season, a record-breaking 10.1 million acres had been burned.

The most interesting thing about the major upward trend in acres burned is the fact that the severity of the Western US drought corresponds with more acres burned.

2020 was historically bad for wildfires. This graph below (found here) shows 2020's amount of acres burned compared to other years since 2001...and the graphic doesn't go through the full season.

The astounding amount of burned acres in 2020 was due to major drought combining with rare tropical moisture and some abnormal wind events to provide optimal conditions (lightning strikes, dry fuels) for massive wildfires. 

The August Complex Fire in Northern California burned an incredible 1 million acres in 2020, contributing to California's total of 4.5+ million acres burned in one season alone. This record amount was caused by extremely dry conditions in California, something that is already occurring this year due to little precipitation.

So...we have learned how drought can wreak havoc in fire season, increasing the length of the season and in turn the acreage burned. 

Now to answer the question...how will drought impact the upcoming fire season?

In part 1 of the drought series, I showed this graphic that shows percent of average snowpack. Since most of the Western US with the exceptions of WA, MT, and WY has below average snowpack, more fires are possible because fuels (what fires need to burn) are already dry and will ignite very easily across a large area of the Western US.

Many people worry about California in particular, where large and destructive fires have become the norm. This tweet from NIDIS Drought explains the forecast for 2021.

It can be assumed that any areas with dry vegetation and little precipitation (especially due to drought) will be more likely to be impacted by wildfires in the upcoming fire season.

In fact, fires are already burning. The National Interagency Fire Center (great resource for current fire news across the US) reports that 457,000 acres have burned in the US so far in 2021 (about half of the long-term average).

The fire season is average so far, but expect it to get worse through the next few months. This will not be the last blog about wildfires this year. Stay tuned for updates throughout the summer as wildfire season worsens.

Found here (WA DNR Twitter).

Found here.

Thank you for reading the Western US Drought series! I hope you have become better informed on the seriousness of the drought that is occurring across the Western US. If you enjoyed this series and would like more blogs like it, please leave a comment and let me know!

Western US Drought Part 2: The Effects

This blog is Part 2 of a three part series about the ongoing major drought in the Western US. Check the previous post for Part 1 (current drought outlook). 

We previously examined the current outlook of the Western US drought. Now, it's time to take a look at some of the drought's effects, in particular the impact on water supply. 

Let's begin...

One of the most critical reservoirs for water supply in the Desert Southwest is Lake Mead. This is the reservoir created by Hoover Dam on the Colorado River, located on the border of Arizona and Nevada. (Map below).

Lake Mead supplies water for about 25 million people (National Park Service), and nearly all of the water supply in Las Vegas and surrounding areas comes from Lake Mead. 

In short...Lake Mead is critical to the water supply for millions of people in the Desert Southwest. 

The extraordinary reduction of water in Lake Mead is seen in this AP Photo, with a marina in the foreground.

The US Bureau of Reclamation (manages water storage/dams across the country) reports that Lake Mead is "full" at 1,229 feet above sea level (this last happened in summer 1983...since then the lake level has slowly declined). The current level as of May 2nd is 1,079 feet, a whopping 149 feet below full capacity. 

Lake Mead 1984 to 2016 interactive comparison: NASA Earth Observatory

This is only expected to get worse. Below is an informative graphic from US Lakes Online showing the current level of Lake Mead compared to other recent years.

The lake level is currently second lowest only to 2016, a very dry year. It is alarming that the level is already lower than other drought years, a sign that things are getting worse.

In late April 2021, 8 News Now Las Vegas reported that current projections show Lake Mead dropping to the lowest level on record within the next 20 months. The record low level is 1,071.6 feet (June 1981). This record could be long gone in the next couple years, with projections that Lake Mead will drop beneath 1,050 ft. by the end of 2022. (A level of 895 feet is needed for the water supply to be cut off...we are nowhere near that).

So...what does this mean? A recent article from The Salt Lake Tribune reported that if the lake is not above 1,075 feet by August 2021, a water shortage declaration will be issued. This will impact the states of Arizona, Wyoming, New Mexico, Utah, Colorado, Nevada, and California. 

Lake Mead Current Lake Levels: US Lakes Online

Lake Mead is not the only large reservoir impacted by the drought. Lake Powell, the reservoir upstream of Lake Mead on the Colorado River and formed by the Glen Canyon Dam, is also losing water. (map below)

At the current rate of water loss, Lake Powell will reach its lowest level since 1968, the Lake Powell Chronicle reported in mid April 2021.

A completely exposed boat launch on Lake Powell. Photo by National Park Service, found here.

Current water levels paint a grim picture for Lake Powell. The graphic below from US Lakes Online shows current levels compared to previous years since 2016.

2021 is taking a nosedive as the worst by far since 2016. Snowmelt might help the level some, but considering the snowpack itself is low, don't expect much improvement. Lake Powell supplies some 30 million people with water, so a water shortage here would have large consequences, just like at Lake Mead.

What is being done to combat the major water supply issues?

Not much as of now. The biggest impact right now is residents being urged to prepare for water shortages.

However, in some cities, more desperate measures are being taken. A Chicago Sun Times article from mid April reported on a Las Vegas proposal to ban ornamental grasses. Grass in places like highway medians (picture below of a Vegas highway).

Photo found here.

While this may seem like a very desperate measure, Las Vegas recently went a record 240 DAYS without rainfall. After a dry streak that lasted nearly 2/3 of a year, you can imagine why proposals like this are gaining ground.

Obviously, there are many more impacts that this drought is having on the Western United States, far too many for any one blog post. Many informative articles can be found online, and a lot can be learned from the links in this post.

Stay tuned for Part 3 of this drought series later this week. The next post will talk about the drought’s impact on wildfires and what effect it will have on the upcoming fire season (which has had an early start due to the drought).

The Weather Underground forecast for the upcoming week in Puyallup is below.

Western US Drought Part 1: The Current Outlook

This post is Part 1 of a three post series about the Western US Drought. Stay tuned for upcoming Parts 2 & 3.

For the past few years, most of Western United States has been gripped by a major drought. The areas hit hardest have been California and the Desert Southwest. This blog series will attempt to bring an understanding of the drought situation & impacts to the readers of this blog.

Let’s start with the US Drought Monitor, a drought outlook released every couple days. This outlook is valid as of Thursday (4/29).

The outlook’s categories are in the bottom right corner, ranging from “none” to “exceptional drought.” The most alarming fact right now is the amount of area labeled as severe, extreme, and exceptional drought.

Huge areas of the US are in some kind of drought, even Western Washington, where our dry April landed us in the "abnormally dry" category. But the situation is far worse across parts of Oregon, California, Utah, Colorado, Arizona, New Mexico, and Texas.

The grim situation is easily shown in the graphic below, which shows the percent of average precipitation in the past year.

The color key showing the percent of average rainfall is on the bottom of the map. A large area of the Southwest has received under 25% to around 70% of average rainfall. Rainfall in these areas is low to begin with, so having less than average is much worse in the Southwest than in the marine climate of Western Washington. (Picture average rainfall of 3-5 inches, then getting 25-50% of that rainfall...it’s not a good situation.)

As you would expect, with rainfall far below average, yearly snowpack is also in bad shape across the Southwest.

Snowpack on May 1st ranges from nearly 150% of normal in the Washington Cascades to under 50% of normal in the Great Basin, Sierra Nevada, and Southern Rockies. 

In short...this means that major drought conditions will continue this summer. That can be seen in the Seasonal Drought Outlook below. Pay attention to the brown and yellow shaded areas. Brown means drought persists, and yellow means drought develops.

This outlook is valid through July 31. Drought will likely persist across the entire Western United States with the exception of NW Oregon and Western Washington (next time you water your lawn...remember how fortunate you are that you have the water supply to do so).

Some impacts of this will likely range from water shortages to a longer and generally worse wildfire season. Images like the one below of Lake Mead will become more common.

Stay tuned for Western US Drought Part 2: The Effects, coming out on Monday. We will examine how the drought has impacted everything from depleted reservoirs to the battle over what grass is “necessary” in metro areas.