On July 15/16, a massive lightning storm initiated several major wildfires east of the Cascade crest.
As shown below, this was one of the most extreme lightning events in Northwest history.
This story has escaped the notice of the media. Furthermore, several media outlets (including KING-5 news and the NY Times) and podcasters/Youtube channels have claimed that Northwest lightning has increased over time due to climate change. (see example below)
The data is clear: the major wildfires that occurred during the past month have little to do with climate change, but were associated with a very unusual "lightning storm" of extraordinary intensity.
As I will demonstrate below, there is no upward trend in Northwest lightning, which indicates that global warming is not a major driver of regional lightning frequency.
There are two major lightning networks that cover our region and beyond: the UW World Wide Lightning Location Network (WWLLN) and the Vaisala National Lightning Detection Network (NLDN).
I first asked UW Professor Robert Holzworth and Scientist Katrina Virts, who run the WWLLN network.
I was amazed to learn that WWLLN detected 5,440 strokes over the PNW on July 16, 2026--the most of any July day in the period of record (since 2013, after which the observing network was stable).
Lightning Strikes on July 15-17.
No wonder there were a lot of fire starts!
Many are concerned about global warming, so I asked the WWLLN folks to see a plot of lightning over time. Katrina made a plot of the number of lightning days per month over the Pacific Northwest (below):
The lightning numbers are DECLINING. And this is a period of substantial global warming. Global warming is NOT contributing to more lightning over our region!.
To get an independent check on these lightning numbers, UW Research Meteorologist Jeff Baars used a completely different lightning network (NLDN), which goes back until the late 1980s.
For this network, July 16 was the third greatest July lightning day since 2013. And examining a far longer period, we see that there is no increasing trend in regional lightning...in fact, a modest decline.
So what should you take away from all this?
The lightning numbers are DECLINING. And this is a period of substantial global warming. Global warming is NOT contributing to more lightning over our region!.
To get an independent check on these lightning numbers, UW Research Meteorologist Jeff Baars used a completely different lightning network (NLDN), which goes back until the late 1980s.
For this network, July 16 was the third greatest July lightning day since 2013. And examining a far longer period, we see that there is no increasing trend in regional lightning...in fact, a modest decline.
(1) The July 2026 lightning event was unusually extreme in terms of the number of lightning strikes, greatly increasing the number of fires.
(2) There is no observational evidence that global warming/climate change is contributing to more lightning strikes (and thus wildfires) over the region.
The latter observational result suggests that some modeling studies, which suggested the opposite, are in error. Clearly, they possess some flaws in their methodology or approach.
I agree with the finding that there have been fewer lightning storm days in recent years in Eastern Washington. A long ago study was made of the average number of lightning storm days during the main summer season, June through September, using the reports from fire lookout stations covering 1930s into the 1950s when lookout stations were numerous. This report showed the average number of lightning days in July and August was about 10 or 12 along the Cascade east slopes, and about double that number from the central Okanogan to the northeast part of Eastern Washington. In recent years I do not think we have come close to that number of lightning days. However, when it comes to fire starts from lightning storms, I think it is a different picture. Lightning does not start many fires if the fuel is moist so wet lightning storms or those occurring after a cool, wet period are not big fire starters even though there may be many lightning strikes. It is lightning accompanied by little or no rain and hitting fuel that has been dried by a long period of warm, dry weather that starts most of the fires. And because it has been warm and dry for a long period, any wind causes these fires to spread rapidly. We saw this situation in late August last year along the Cascade east slopes and we are seeing it over a larger area this year. An extended period of warm, dry weather prior to the lightning is nearly always associated with these big fire events and to say that warm temperatures are relatively unimportant is not accurate. I have witnessed lightning storms that produced many ground strikes but few fires resulted either because there was good moisture with the storm or it came following a mainly cool, wet period.
ReplyDeleteGlad we agree that the lightning was way down. Fuel moistures were near normal when the fire started (e.g., check out the 100 hour fuels) and this is the dry season. Temperatures during the prior two weeks were NOT particularly warm.
DeleteWxman - you really need to present more data when you assert things to be true. You tend to state generally true things and then extrapolate without data in order to confirm a hypothesis.
DeleteThe satellite images of the smoke plums that cover the entire Pacific Northwest on up into southern Canada are just incredible. How many square miles of smoke is that?
ReplyDeleteAgree, this summer has not been particularly warm, mostly low to mid 80's, most days, with periodic bouts to around 90 or so, at least in western Washington during the day.
ReplyDeleteLows seem to be mid to upper 50's for the most part, even if hot during the day, it just takes a bit of time to cool down.
Wouldn't it be more meaningful to look at the number of lightning strikes per year, or the distribution of lightning strike days? E.g., how many days there were per year with >1000 strikes, >500, >100, etc.,?
ReplyDeleteDoes global warming cause arsonists to set fires?
ReplyDelete'Agree with those who feel this has been a pretty temperate summer (not a sizzler). I don't recall many summers without rain here in Whatcom, at least near Mt Baker - clouds do form here at the edge of the range. We didn't experience any lightning events that I know of in our immediate area during that timeframe.
ReplyDelete