Cameron Peak Fire becomes the largest on record for Colorado

October 14th, 2020 |

GOES-16 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), “Clean” Infrared Window (10.35 µm, bottom left) and Fire Temperature RGB (bottom right) [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), “Clean” Infrared Window (10.35 µm, bottom left) and Fire Temperature RGB (bottom right) [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm), “Clean” Infrared Window (10.35 µm) and Fire Temperature Red-Green-Blue (RGB) images (above) showed diurnal changes in the Cameron Peak Fire in northern Colorado on 14 October 2020. Aided by strong westerly winds at the surface (with peak gusts in the 50-70 mph range), the fire’s thermal signature initially began to increase in areal coverage and spread rapidly eastward — however, following the passage of a cold front around 18 UTC, an influx of cooler air with higher relative humidity halted this eastward expansion of the fire (with the thermal signature then retreating westward and diminishing in size). By that evening, the fire’s total burned area had grown to 158,300 acres, making it Colorado’s largest wildfire on record. While there was some pyrocumulus development over the fire source region, this large and hot fire did not produce a pyrocumulonimbus cloud.

Another view of the fire using 5-minute imagery from GOES-16 provided quantitative products such as Fire Power, Fire Temperature and Fire Area (below) — these 3 products are components of the GOES Fire Detection and Characterization Algorithm (FDCA). Surface observations showed that during the morning hours smoke was restricting surface visibility to 3 miles at Fort Collins (KFNL) and 5 miles at Greeley (KGXY).

GOES-16 Fire Temperature (top left), Shortwave Infrared (3.9 µm, top right), Fire Power (bottom left) and Fire Area (bottom right) [click to play animation | MP4]

GOES-16 Fire Temperature (top left), Shortwave Infrared (3.9 µm, top right), Fire Power (bottom left) and Fire Area (bottom right) [click to play animation | MP4]

GOES-16 True Color Red-Green-Blue (RGB) images created using Geo2Grid (below) indicated that one portion of the Cameron Peak Fire smoke plume was transported eastward across parts of Nebraska and Iowa, with another part of the plume moving southeastward across Kansas.

GOES-16 True Color RGB images [click to play animation | MP4]

GOES-16 True Color RGB images [click to play animation | MP4]

A toggle between Terra MODIS True Color and False Color RGB images on 14 October from the MODIS Today site (below) showed the  Cameron Peak Fire smoke plume as well as its large burn scar (shades of red).

Terra MODIS True Color and False Color RGB images on 14 October [click to enlarge]

Terra MODIS True Color and False Color RGB images on 14 October [click to enlarge]

In a comparison of MODIS False Color RGB images from Aqua on 13 October and Terra on 14 October (below) the growth of the Cameron Peak Fire along its southeast flank was evident — and several other large fire burn scars were evident across Colorado and southern Wyoming.

MODIS False Color RGB images from Aqua (13 October) and Terra (14 October) [click to enlarge]

MODIS False Color RGB images from Aqua (13 October) and Terra (14 October) [click to enlarge]

Additional aspects of this fire and its environment are discussed here.

Upper-tropospheric stability around wildfires

October 14th, 2020 |

Day Land Cloud Fire RGB over northern Colorado, 1721-2216 UTC, 154 October 2020 (Click to animate)

Strong winds on 14 October invigorated the Cameron Peak fire to the west of Fort Collins, producing an extensive smoke plume.  The Day Land Cloud Fire RGB, above, includes the near-infrared 2.25 µm channel (GOES-16 Band 6) that shows the active fire in red and the ‘Veggie’ Band at 0.87 µm (a useful channel to show the burn scar to the west of the active fire). Note that a second fire is detected shortly after 2100 UTC in north-central Grant County to the west-southwest of the Cameron Peak fire.

Vigorous fires occasionally force pyrocumulonimbus clouds (as shown here, for example, for the Cameron Peak fire in early September).  What tools are available in mid-day to assess the likelihood of a pyrocumulonimbus?

NOAA-20 overflew Colorado (from this site) shortly after 2000 UTC on 14 October 2020.  NUCAPS Profiles from that overpass can be used to diagnose atmospheric stability. Gridded NUCAPS fields show lower stability south of the fire, and greater stability north, over Wyoming (the colorbar of the field has been altered to highlight lapse rates between 5 and 8 C / km). A similar plot showing 700-300 mb lapse rate also shows the increase in stability to the north.

The increase in stability as the airmass moves from the north will affect the likelihood of Pyrocumulonimbus development.  This (large) 4-panel animated gif (from this blog post) shows the evolution of the fire — with 1-minute time-steps — during the day on 14 October.

GOES-16 Visible Imagery (0.64 µm) and gridded NUCAPS fields of 500-300 mb Lapse Rate (Click to enlarge)

The six NUCAPS soundings that surround the fire show the steep upper-tropospheric lapse rates, below.

NUCAPS Profiles at 2000 UTC surroundings the Cameron Peak Fire (Click to enlarge)