Thursday, October 22, 2020

East Troublesome Fire Blowup

 It's October 22nd.  I repeat October 22nd.  

Yesterday, the East Troublesome Fire in Grand County Colorado exploded.  It's worth taking a look at a couple of fire maps to illustrate the explosive growth.

At 2055 on the evening of October 20th, the fire perimiter covered 19,086 acres.  

At 0030 hrs on the evening of October 22nd, it was 125,602 acres.   

I am now seeing reports that the fire has jumped the Continental Divide to the east slope of the Front Range.

Radar imagery from yesterday shows no echoes associated with the fire at 1911 UTC (1311 MDT).

Source: NCAR/RAL

By 2057 UTC (1457 MDT), echoes extended from the fire area near Granby (GNB on the map below across the Continental Divide, an indication of both explosive growth and strong flow.  

Observations from Kremmling, just upstream of the fire, over the past five days show that yesterday was the warmest day of the period, with the lowest relative dewpoints and relative humidities.  Winds were stronger and more sustained from the southwest as well.  

Source: MesoWest

Observations from the Granby Airport tell a somewhat similar tale.  Yesterday was a couple of degrees warmer than the previous day, with lower dewpoints and relative humidities.  Wind gusts were also stronger. 

Source: MesoWest

Additionally, the flow at 700 mb, about 10,000 ft above sea level, also strengthened.  Analyses for 0000 UTC 21 October (1800 MDT Tuesday) and 0000 UTC 22 October (1800 MDT Wednesday) and show an increase from 10-15 knots to 20-25 knots between the two days.  

Note also that the 700mb temperature increased about 4˚C, even greater than the maximum temperature increase at valley stations, and that radar echoes appeared yesterday afternoon with the fire blowup.  

As much as I like to poke fun at Colorado for its minimal snowfall and powder days, I am rooting for them to bet a big dump and bring an end to this fire season.  


  1. Thanks for the post, good info. This visible 1-hour Geocolor sat image loop is amazing. Right now it is 37°F with low clouds and fog in the Denver area, but in the 60s with strong west winds fanning the fire above about 8000 ft. Lots of smoke is blowing west over the top of the low clouds on the plains.

  2. Jim, would it be fair to say that climate change has made conditions worse?

    1. An easy question with a complicated answer. Ecosystem health, wildfire behavior, weather, and climate are all intrinsically linked.

      It is clear that climate change is affecting western wildfires, although also that other factors contribute. It's easiest for me to quote the 2018 National Climate Assessment (

      "Climate change has led to an increase in the area burned by wildfire in the western United States. Analyses estimate that the area burned by wildfire from 1984 to 2015 was twice what would have burned had climate change not occurred. Furthermore, the area burned from 1916 to 2003 was more closely related to climate factors than to fire suppression, local fire management, or other non-climate factors.

      Climate change has driven the wildfire increase, particularly by drying forests and making them more susceptible to burning. Specifically, increased temperatures have intensified drought in California, contributed to drought in the Colorado River Basin, reduced snowpack, and caused spring-like temperatures to occur earlier in the year. In addition, historical fire suppression policies have caused unnatural accumulations of understory trees and coarse woody debris in many lower-elevation forest types, fueling more intense and extensive wildfires."

      Note that I have stripped out the figures and references, but they are available in the link above.

      Any individual fire is going to be highly dependent on the weather and ecosystem conditions. I don't feel I have enough knowledge of those conditions in this instance to comment on the specific role of climate change in this specific event. My view, however, is that the fingerprints of climate change are readily apparent in western wildfire statistics today.

  3. I lived in the Fraser valley a few years ago and climate change has nothing to do with the fire just wind and lots of fuel. You see 10 years ago the beetle kill hit that area super hard +80% trees died and have been drying out and waiting for a reason. No this isn't the first time the beetles came through it happened in 1979 and 1954 as well. You see it takes a cold winter of -20° for weeks to make the trees freeze and expand enough to crush the beetles. Just be glad they missed Utah. Maybe there is a better answer to why the west is so dry. Maybe you should ask why has the high pressure off the coast of CA been there since March? It might be man manipulated but I don't think it has anything to do with climate change.