Got a connection? – Is it good?

Are from Cliff . Massive Weather Blog

Cliff Mass,

Last Thursday, December 30, strong winds led to a large grass fire that quickly moved into residential areas around Superior, Colorado — a town between Denver and Boulder.

Driven by winds in excess of 100 mph plunging down the eastern slopes of the Colorado Front Range, the man-made fires moved rapidly to densely populated areas, with about 1000 homes. lost, several businesses destroyed or damaged and two people unoccupied.

Large tracts of hay surround the burning homes and businesses of nearby Superior, CO and Louisville.
Within hours of the event, several media outlets including the Washington Post, Seattle Times, National Public Radio, NBC News and Axios (to name just a few), made widespread claims that the fire was the result. of global warming (or “Climate Change” in modern vernacular) or global warming plays an important role.
Politicians, such as the Governor of Colorado, blame climate change, as do groups of climate activists.

The truth is different and very clear. This event has little to do with climate change. And it’s very easy to show this.
In this blog, we will look at why this terrible tragedy happened and what steps must be taken to prevent it from happening again.
We will look at each of the necessary components of this fire, and ask whether climate change might be contributing to this.
Ignition source: No connection to climate change.
The fire is man-made, not naturally ignited (no lightning).
Climate change has nothing to do with ignition.
The large increase in population in the area during the past 50 years clearly makes accidental fires more likely.

Potential ignition location
Strong winds: No connection to climate change
An important aspect of this event was the strong winds, which accelerated down the eastern slopes of the Rocky Mountains ahead.
Such winds are connected to high amplitude mountain waves that can be generated under suitable meteorological conditions, including strong west-to-northwest currents approaching the Rockies and a stable layer near or just above the crest. Mountain. Such conditions occurred on December 30, and strong winds were forecast using high-resolution numerical forecasting models (e.g. NOAA/NWS HRRR models).

There is no reason to assume that this lowering wind storm is the result of global warming, enhanced by global warming, or occurring more frequently by global warming.
In fact, the opposite is possible.
Although winds reached 100-115 mph in some locations, some historic storms in the forward range have been stronger, such as the events of 1972 (144 mph) and 1982 (140 mph).
Downstream wind storms are not unusual along the Colorado Front Range and are most frequent during the cool season (November to January) as shown below. There seems to be a downward trend in the number of events that are sharply decreasing, which suggests that global warming is not encouraging them.

In fact, several studies, looking at global climate patterns forced by increases in greenhouse gases, have found that the conditions that produce wind storms in the front band will become less often and weaker as the earth warms (for example, this reference).
Fuel of Fire: Hay. There is no connection to global warming.
So if the fire burns and the essential strong winds have nothing to do with global warming, the only possibility left is fuel, in this case the vast grasslands of the region. . But as I’ll show, it’s inconceivable that global warming has any role in the fast-moving grass fires.
As shown in the figure below (by google maps), the area just west of Superior, CO is characterized by extensive grasslands. These grasses grow and green well in the spring and naturally turn brown and dry in the summer. Such grasses are called fuel dies in an hour, which means that no matter how moist they are, they can dry enough to burn in ONE HOUR at drying conditions.
And few environments are drier than the combination of strong winds and low relative humidity that accompanies low winds (relative humidity is about 23% on the morning of the storm).

So whether the previous period was warm, wet, humid or dry, THAT DOESN’T PROBLEM. The windstorm event itself ensures that the grass is ready to burn.
So the claims by some activists that a months-long drought in the fall caused the bushfire event are clearly false.And the claims that global warming has helped prepare the grass for burning are horribly wrong.
Furthermore, 10-hour dead fuel moisture measurements (for plants slightly larger than grass) in the nearby US RAWS (Sugarloaf Mountain) showed a humidity of about 9% in the days prior, near as usual for this time of year (9% for December). I should note that it rained on December 25th.

% Moisture Moisture Dead fuel for 10 hours at the Sugarloaf RAWS observation site.
But there’s more than that.
This year the grass is especially abundant, not because of the drought, but because the area has experienced it a particularly wet spring and early summer. To show this, below is the cumulative rainfall observed over the past year in Boulder, Colorado, with normal values ​​also shown.
Precipitation was normal around March 1st but by June 1 the rainfall was much higher than normal…and that heavy rainfall continued into the summer. The result is enhanced grass growth. And there is no reason to expect that global warming increases the amount of rainfall in spring–There is no climate model output to support that.
You will notice that the whole year is almost normal. By the way, the ice in the mountains above Boulder was above normal last winter.

The bottom line in all of this: there is no clear or logical link between the dry grass that created this tragic fire and global warming.
Lack of snow: A global warming connection?
Another confirmed link between global warming and fires is the lack of snow this year due to warm, dry conditions this fall. But that’s no support as well.
First, having little or no snow on the ground is not unusual for the Boulder, Colorado area in late December. In fact, only about one-third of winter days get 1 inch of snow. above the ground (a reference here), with an average snow depth of about 1.5 inches. And wildfires can occur in grasslands with several inches of snow on the ground.
An interesting question is whether global warming will produce drier/warmer autumns along the Front Range (little evidence for that). And another is whether there is an alternative explanation for this year’s dry/warm fall (yes).
If global warming is important for autumn weather along the Front Range, one should find significant trends over the past decades in precipitation, drought index and summer temperatures. collect. Let’s look at this using NOAA/NWS Climatic Division Data for September-December conditions for 1950-2020.
For precipitation (below), there is no obvious upward or downward trend:

And for Palmer drought index, including temperature, there are no obvious trends, but there are a lot of ups and downs.

As for temperature, there is only a slight warming (~1F).

Thus, it seems unlikely that long-term global warming in this region is contributing to the arid and dry conditions.. Or lack of snow
But something could be contributing to the dry, warm, and snow-laden conditions this fall in the Colorado Front Range: La Nina.
We are currently in a mild La Nina year, with the central tropical and eastern Pacific Ocean having below-normal sea surface temperatures. La Nina affects the circulation of the atmosphere across the entire planet, and one “remote connection” of La Nina is the warm, dry conditions in eastern Colorado.
To demonstrate this, I looked at the correlation between tropical sea surface temperatures and temperature/precipitation conditions in the United States using the excellent NOAA ESRL website.
La Nina year associated with drier-than-normal fall over Colorado (orange/red)

And warmer than normal temperature (green/blue).

So why blame global warming on warm/dry conditions, when long-term trends don’t signal global warming and La Nina provides a ready-made explanation? Some media people don’t make money!
Major contributors to the disaster
More evidence clearly shows that global warming has little to do with the catastrophic Marshall Fire in Colorado. Strong/dry winds from downhill, lush blades of grass for a wet spring, and human ignition account for the flames.
This is a disaster that is already happening and human actions and decisions have contributed to the problem. Let me note a few of them.
Large population growth in the region
From 1950 to the present day, there has been an explosion of population growth in the region, which has not only increased the vulnerable population, but also increased potential ignition sources and fuels (e.g. homes and buildings). ). For example, the town of Louisville has seen a population increase from about 2000 to 20,000 during the past 70 years.
Grasslands next to densely populated areas
Ironically, for environmental reasons, extensive traces of “natural” grassland have been reserved as part of the Boulder County Comprehensive Plan, with dense housing development next to wilderness areas (see map below showing Protected Environmental Conservation Areas, with a red star where homes are lost)

As a result, there are large areas of burnt grass adjacent to densely populated areas, and worse, these grassy areas are often located to the west (west) of developed areas. Therefore, we have a extremely dangerous situation where the windiest areas, just east of the Front Range, are dominated by grasslands. Any ignition would lead to fires rushing eastward into densely populated areas. Upwind combustible grasslands of major housing developments. It could hardly be worse.
Dense home development
With so much land set aside for wilderness areas, less is left for housing and development. As a result (and perhaps also to increase profitability), many housing developments near Superior and Louisville, CO have had homes spaced very close to each other (see image below).
So once a house catches on fire, neighboring houses are more likely to catch on fire. In many wildfire situations, homes provide large amounts of fuel to help grow and spread the fire, something that is well documented in the Paradise, CA Campfire, and is evident in the case of wildfires. this.

Invasive weeds are highly flammable
Over the past century, highly flammable invasive grass species (e.g., cheek grass, oatgrass) have migrated into the area, significantly increasing the likelihood of wildfires. Limited steps have been taken to resolve the issue.

Lack of safe zone
There has been little effort to create large enough grass-free safe areas around urbanized areas.
Historic fires in the area
The fires are frequent visitors to Boulder County, but most recent fires have been in dense wooded terrain, often covered with grass (see map below). Some fires are primarily grass fires, but do not spread to densely populated areas.

Summary
Global warming has very little to do with the destructive wildfires that occurred in Colorado on December 30th. Global warming narrative promoters for this event (for example, some media) media, politicians and activists) are misinforming the public.
But it’s worse than that. Blaming global warming undermines efforts to clearly identify risks and take effective, coherent actions to reduce the likelihood of such wildfire disasters occurring again.