The media and social media are abuzz with talk about the upcoming "Super" El Niño, with forecasts of low snowpack, drought conditions, and massive wildfires (see sample below).
My local newspaper and some amateur social media are making similar claims.Few of these scary claims are supported by the facts: in reality, the outlook is quite favorable for our region if a "Super El Niño" continues to develop.
Let me prove this to you.
Surprisingly, there is nothing called a "Super El Nino" in the scientific world.
If the temperature anomaly (difference from normal) of the ocean surface in the tropical Pacific is 1.5 to 2 C above normal, it is called a strong El Niño. More than 2C, a very strong El Niño. The media calls this a "super"; the scientific community does not.
Below is the latest forecast by NOAA. They are predicting a very strong El Niño this autumn (peaking around 2.2 C above normal).
There is little doubt we will get a very strong El Nino, but this is not unprecedented, with others occurring in 1982-1983, 1997-1998, 2015-2016, and 2023-2024 (others have occurred before as well).
A KEY point is that very strong El Niños are very different animals than their more moderate cousins. With different impacts.
Moderate to strong El Niños are typically associated with less snowpack and drier-than-normal conditions.
Very strong El Niños bring near-normal snowpack and plenty of moisture.
Thus, our water resources are generally fine with very strong El Niños like the upcoming winter.
Want the proof?
Below is a plot of precipitation from October to April (our wet season) since 1980. The red arrows indicate very strong ("super") El Nino years, and the yellow line is the average of the period (1980 to today).
Very strong El Niño years are NOT particularly dry... their average is a bit ABOVE NORMAL.
What about snowpack?
Let's check out a few sites, looking at April 1 snowpack (which is generally the date used for evaluations).Crystal Mountain Ski area (around 6000 ft)? Snowpack during very strong El Niños is nearly normal (horizontal line) during such years.
The much lower Stampede Pass (4000 ft)? Same story.
Even LOWER at Snoqualmie Pass (below). Same story...nearly normal snowpack during very strong El Niño years!
Very strong El Niño years have near-normal snowpack in our mountains. I could show you a dozen other locations: same story.
What about temperature? Over Washington State at the surface, very strong El Niño years are about 1°F above normal, although one was below normal (2024).
With normal rain and mountain snow during a very strong El Nino year, the expectation is that there will be plenty of water next year for our region's needs.
So those predicting drought, drastically reduced snowpack, and enhanced wildfires over the region will have a lot of the proverbial egg on their face next summer.
So what exactly does a very strong El Niño do to the larger-scale atmospheric circulation around here? I am a weather scientist and am curious!
Below is the average of the upper-level heights at 500 hPa (think pressure at 18,000 ft), showing the difference from normal for October through March of a very strong El Niño year. Purple is much lower than normal heights/pressure (a strong trough).
Mama mia! A HUGE intense low-pressure area over the north Pacific!
Let's look at the local implications of this intense pattern by examining the difference from normal in the winds around 5000 ft for such a very strong El Nino year (below).
There are greatly enhanced winds from the southwest offshore, bringing in lots of moisture into the West Coast. That means more precipitation. NO DROUGHT.
To demonstrate this, below is the difference in precipitation from normal for such very strong El Niño years. A lot more precipitation over the West Coast, with the greatest increase over northern CA and southern Oregon.
Our region will be a bit warmer than normal, but the additional moisture should result in near-normal snowpack in the mountains above 3500 ft. Lots of water to fill reservoirs and moisten the soils.
No problem.
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Fair on El Nino. Not fair on the last paragraph. "A bit warmer than normal" + "fine above 3,500 ft" + "No problem" is three claims, and the middle one quietly concedes the thing the third one denies. Half the Cascades' snow-storage sits below your line. Say now what April 1 number at Snoqualmie would make you wrong.
ReplyDeleteYou are not correct. Snoquamie at 3000 ft shows the same thing! Added it to the blog.
DeleteA blatant AI comment
DeleteYep looks AI generated. Typos and grammar will prevail. Todays 'real' people tend to not use auto correct, nor correct typos, this makes us human now in our electronic world. This post uses mutiple spaces between words. Big clue. Want to be known as human on the web, dont try for perfection. But also, dont be percect with simple mistakes. My way, type the way i think it, not worry about it. Thanks cliff, keep it real!
DeleteIt's interesting to bring up 1997-1998, because many in the Inland Northwest remember it was a strong winter with lots of snow, but most don't recall a very strong El Niño.
ReplyDeleteCliff Mass - "fine above 3,500ft"
ReplyDeleteYou - "Half the Cascades' snow-storage sits below your line" - citation needed for this outlandish claim
Was there any correlation between the very strong El Nino in 1997-98 and the substantial rain that led to the Magnolia Brdige landslide in January 1997 or the record snow that Mt Baker received (1,140 inches) in 1998-99?
ReplyDeleteMr. Cliff Mass, I appreciate your thoughts with data and stats to show the meaning of how "Strong El Niño's differ in their affects on Winter" compared to other media and respected meteorologists. It's refreshing and certainly makes sense to read and understand for an interested 37 year old weather buff like me
ReplyDeleteCliff-- This is a request from left field. I grew up on a dairy farm in Whatcom County. Some time in the late 1950s, 1957 or 1958 maybe, we experienced a severe summer drought. Wells went dry. My dad was scared our well would go dry. Fortunately, it didn't, but some of his fellow dairy farmers had to bring in tanker trucks to water their herds. The next year, he had our well deepened. Here's my question: do your records show this drought? Do they correlate to El Nino conditions? I've been curious about this for years because my dad, who was level-headed and not easily upset by the weather, was more shaken than ever before or after.
ReplyDeleteThanks, Marv Waschke
Thanks.
I believe you're thinking of the summer of 1958. That was the warmest summer in our history [up to that point, not exceeded until I believe the summer of 2014 or 2015]. Even as a 3-year-old I was aware of how hot it was then.
DeleteNice summary of big picture. I have lived in the El Nino west (Calif., Oregon, Wash, Idaho) since 1950. Yep, some El Ninos are wet and warm some are dry and warm. Climate change will influence this upcoming very strong El Nino no doubt. Be interesting to experience (I live in Bend, OR) this upcoming weather event. Nice over view. Thanks.
ReplyDeleteQuestion for you Cliff - I see looking at the latest eastern Pacific SST map from 28 Aug NOAA that the SST's off of the immediate Peruvian coast are +5 C, not in the +2.1..ish range predicted. How is that 2.1 number calculated then - is it an integrated value over a much broader area?
ReplyDeleteApril 9: We are certainly moving towards El Niño conditions, but I would be careful about assuming that the Super El Niño prediction of the European Center is correct, due to the spring forecast barrier and the larger differences between other modeling system forecasts.
ReplyDeleteJune 23: Looking at a collection of many forecast models (below) provides a similar picture: a substantial weakening of El Nino during the winter.
August 28: There is little doubt we will get a very strong El Nino
By April, the ski season is well over, what would this data look like in January or February? Anecdotally, we have had a few "miracle March" snow fall events that made the season look normal, even when lifts weren't open until after Christmas, and every snow we got turned to rain at the end of the storm. Is there data available to see what this compares at the end of Dec,,,Jan, Feb?
ReplyDeleteI guess what you are saying is that the news media sensationalizes something that likely as not won't be all that sensational.
ReplyDeleteYes, that's how their business model works. And people buy into it.
DeleteEarly 2016 had a very strong El Nino in place. The temperature increase was notable, but I also remember there being much more rain than I would've hoped for during an El Nino winter. It was likely a winter with low snowpack but good overall water resources.
ReplyDeletePrecipitation will increase soon in the western U.S.
ReplyDeletehttps://www.cpc.ncep.noaa.gov/products/stratosphere/strat_int/gif_files/gfs_o3mr_200_NA_f000.png
Cliff, one question about the snowpack. You mention that strong El Niño means a normal snowfall. This is contrary to the opinion of one of your peers. This is from the BBC website. : “ Further north in the US and in Canada, the combined impact of El Niño and marine heatwaves is expected to reduce snowfall, says Larry O'Neill, professor at Oregon State University and director of the Oregon Climate Service. The last huge Pacific marine heatwave, coined "the Blob", led to a record low snowpack in the Pacific Northwest in 2015.” Could you please comment, do you disagree and if so, why? Is he factually incorrect about 2015?
ReplyDeleteRU.... you are misunderstanding. A strong El Nino means less snowpack. A very strong one indicates near normal. The BLOB is something else. Marine heatwaves are something else...cliff
DeleteI really hope this coming storm doesn't fizzle out or underperform. The first one of the season often does...
ReplyDelete