Large grass fires continue to burn in the southern Plains

April 17th, 2018 |

GOES-16 Shortwave Infrared (3.9 µm) images, with hourly plots of surface reports [click to play MP4 animation]

GOES-16 Shortwave Infrared (3.9 µm) images, with hourly plots of surface reports [click to play MP4 animation]

1-minute Mesoscale Sector GOES-16 (GOES-East) Shortwave Infrared (3.9 µm) images (above) showed a number of “hot spot” signatures (dark black to red pixels) associated with grass fires that began burning in southeastern Colorado, southwest Kansas and the Oklahoma/Texas Panhandles on 17 April 2018. These fires spread very rapidly with strong surface winds (as high as 81 mph at Wolf Creek Pass CO) and very dry fuels due to Extreme to Exceptional drought. In addition to these new fires, hot pixels from the ongoing Rhea Fire in northwest Oklahoma (which began burning on 12 April) were still apparent.

During the subsequent nighttime hours, a strong cold front plunged southeastward across the region (surface analyses) — and on a closer view of GOES-16 Shortwave Infrared images (below), 2 different behaviors were seen for 2 of the larger fires. As the cold front moved over the Badger Hole Fire that was burning along the Colorado/Kansas border, an immediate decreasing trend in hot spot intensity and coverage was noted. Farther to the southeast, when the cold front later moved over the Rhea Fire in northwest Oklahoma a flare-up in hot spot intensity and coverage was evident.

GOES-16 Shortwave Infrared (3.9 µm) images, with hourly plots of surface reports [click to play MP4 animation]

GOES-16 Shortwave Infrared (3.9 µm) images, with hourly plots of surface reports [click to play MP4 animation]

===== 18 April Update =====

A nighttime comparison of (Preliminary, Non-Operational) NOAA-20 VIIRS Day/Night Band (0.7 µm), I-Band Shortwave Infrared (3.75 µm), M-Band Shortwave Infrared (4.05 µm), and M-Band Near-Infrared (1.61 µm and 2.25 µm) images (below; courtesy of William Straka, CIMSS) showed a variety of fire detection signatures associated with the Rhea Fire (283,095 acres, 3% contained) in northwest Oklahoma.

NOAA-20 Day/Night Band (0.7 µm), I-Band Shortwave Infrared (3.75 µm), M-Band Shortwave Infrared (4.05 µm), M-Band Near-Infrared (1.61 µm and 2.25 µm) images [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm), I-Band Shortwave Infrared (3.75 µm), M-Band Shortwave Infrared (4.05 µm), M-Band Near-Infrared (1.61 µm and 2.25 µm) images [click to enlarge]

The early afternoon 1-km resolution Aqua MODIS Land Surface Temperature product (below) indicated that LST values within the Rhea burn scar (which covered much of Dewey County in Oklahoma) were as high as 100 to 105 ºF (darker red enhancement) — about 10 to 15 ºF warmer than adjacent unburned vegetated surfaces.

Aqua MODIS Land Surface Temperature product [click to enlarge]

Aqua MODIS Land Surface Temperature product [click to enlarge]

===== 19 April Update =====

A 30-meter resolution Landsat-8 false-color image from RealEarth (below) provided a detailed view of the Badger Hole Fire, which had burned 48,400 acres along the Colorado/Kansas border.

Landsat-8 false-color image [click to enlarge]

Landsat-8 false-color image [click to enlarge]

Grass fires in northwest and southwest Oklahoma

April 12th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, top) and Shortwave Infrared (3.9 µm, bottom) images, with hourly plots of surface reports [click to play MP4 animation]

1-minute Mesoscale Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above) showed the development and rapid spread of grass fires in northwest Oklahoma on 12 April 2018. Hot fire pixels are highlighted as red on the Shortwave Infrared images — and the rapid northeastward run of the larger fires was very evident. The intense heat of the fires produced pyrocumulus clouds, which could be seen on the Visible images. Additional images are available on the Satellite Liaison Blog.

SPC had highlighted parts of New Mexico, Colorado, Texas and Oklahoma as having conditions favorable for Extreme wildfire behavior due to strong winds, hot temperatures and very dry air behind a dryline boundary (below). Note that the surface temperature / dew point depression at Woodward, Oklahoma (KWWR) at 2255 UTC on 12 April was 100 ºF (temperature = 97 ºF, dew point = -2 ºF), with southwesterly winds gusting to 35 knots or 40 mph.

SPC Day 1 Fire Outlook [click to enlarge]

SPC Day 1 Fire Outlook [click to enlarge]

===== 13 April Update =====

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.9 µm) images [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.9 µm) images [click to enlarge]

The fires in northwestern Oklahoma continued to burn into the following night — Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.9 µm) images at 0837 UTC or 3:37 AM local time (above) revealed the bright glow and hot fire pixels associated with the 2 large fire complexes in Woodward County (34 Complex Fire) and Dewey County (Rhea Fire). At least 2 fatalities (Wildfire Today | media report) have been attributed to the larger and longer-burning Rhea Fire in Dewey County (which had burned an estimated 241,280 acres by mid-day on 14 April).

During the following daytime hours of 13 April, GOES-16 “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (below) showed the smoke plumes and hot pixels of the northwestern Oklahoma fires. The surface cold front moved over these fires around 18 UTC, with smoke transport transitioning more toward the east then southeast.

GOES-16

GOES-16 “Red” Visible (0.64 µm, top) and Shortwave Infrared (3.9 µm, bottom) images, with hourly plots of surface reports [click to play MP4 animation]

Farther to the southwest, new grass fires which began burning west of the Texas/Oklahoma border after 17 UTC quickly raced eastward and crossed the border into southwestern Oklahoma after 20 UTC (below).

GOES-16

GOES-16 “Red” Visible (0.64 µm, top) and Shortwave Infrared (3.9 µm, bottom) images, with hourly plots of surface reports [click to play MP4 animation]

===== 14 April Update =====

Three nighttime comparisons of (Preliminary, non-operational) NOAA-20 and Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.75 µm) images — each image pair separated by 50 minutes — (below; courtesy of William Straka, CIMSS) showed the bright glow and thermal hot spots of the ongoing Rhea fire complex.

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.75 µm) images at 0737 UTC [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.75 µm) images at 0737 UTC [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.75 µm) images [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.75 µm) images [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.75 µm) images [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.75 µm) images [click to enlarge]

===== 15 April Update =====

250-meter resolution Terra MODIS true-color and false-color Red-Green-Blue (RGB) images from MODIS Today (below) showed the burn scars from the 34 Complex and the larger Rhea Fire at 1719 UTC on 15 April 2018.

Terra MODIS true-color and false-color RGB images [click to enlarge]

Terra MODIS true-color and false-color RGB images [click to enlarge]

Wildfires in northeastern Oklahoma

March 24th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and Shortwave Infrared (3.9 µm, right) images, with surface airport identifiers plotted in cyan [click to play MP4 animation)

GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above) showed smoke plumes and fire “hot spots” associated with numerous wildfires burning in northeastern Oklahoma on 24 March 2018.

A comparison of Terra/Aqua MODIS and Suomi NPP VIIRS Shortwave Infrared images (below) showed  higher-resolution view of the fire hot spots.

Terra/Aqua MODIS and Suomi NPP VIIRS Shortwave Infrared images with surface observations plotted in cyan [click to enlarge]

Terra/Aqua MODIS and Suomi NPP VIIRS Shortwave Infrared images with surface observations plotted in cyan [click to enlarge]

Fires over the Texas Panhandle

March 23rd, 2018 |

GOES-16 ABI Shortwave Infrared imagery (3.9 µm), 1905-2058 UTC on 23 March 2018 (Click to animate)

The Storm Prediction Center issued an Extreme Fire Weather advisory for 23 March 2018, and a GOES-16 Mesoscale Sector (#2, from this site) was positioned over the High Plains of Texas to monitor.

The GOES-16 Shortwave Infrared imagery, above, from 1905-2058 UTC on 23 March 2018 shows rapid warming of pixels near Borger TX (KBGD), and then southeast of Borger and northeast of Amarillo (KAMA). Surface observations show gusty southwest winds and low dewpoints, ideal for fire. Under the cirrus shield to the south, decreased solar insolation meant less vertical mixing of dry air and high winds, so dewpoints were higher and winds were weaker, lessening the fire danger.

Note that missing pixels are apparent in the GOES-16 Shortwave IR imagery around 2010 UTC. Quality flags that highlight the extreme warmth of the pixel have been activated, and AWIPS data are reported as missing in those locations.

Visible imagery, both Band 1 (“Blue” Visible, 0.47 µm) and Band 2 (“Red” Visible, 0.64 µm) from the GOES-16 ABI, below, show visible smoke plumes starting around 1940 UTC for the fire near Borger, and closer to 2000 UTC for the fire southeast of Borger. The plumes appear in both visible bands at approximately the same time, although they are more distinct in the blue band because of the enhanced scattering in the atmosphere at that wavelength.

GOES-16 ABI “Blue” Visible imagery (0.47 µm), 1905-2058 UTC on 23 March 2018 (Click to animate)

GOES-16 ABI “Red” Visible imagery (0.64 µm), 1905-2058 UTC on 23 March 2018 (Click to animate)

A qualitative method of identifying fires is the Fire RGB that combines the shortwave IR (3.9 µm, the red component of the RGB) with the 2.2 µm (Green) and 1.6 µm (Blue) reflectance channels. As fires become progressively hotter, they emit more and more radiation at shorter wavelengths that can be detected by the ABI on GOES-16, and this alters the color of the RGB over the fire. The Fire RGB animation is shown below. When the 3.9 µm imagery is missing from AWIPS (2005 UTC, 2007-2011 UTC, 2015 UTC because the pixels are hot enough that quality control flags are activated, so the data are not shown), the red pixels in the Fire RGB turn green because no Red component is present (Click here to see the Fire RGB and Shortwave IR animated 2004-2016 UTC).

GOES-16 ABI Fire RGB imagery (3.9 µm, 2.2 µm, 1.6 µm), 1905-2058 UTC on 23 March 2018 (Click to animate)

There are Baseline products that allow a quantitative estimate of fire properties. The animation below shows the Mesoscale Domain Band 7 Shortwave Infrared (3.9 µm) imagery zoomed in over the Texas Panhandle, at 1-minute time-steps; superimposed on the imagery are the GOES-16 Fire Detection Fire Temperature pixels. Fire Products at present are not produced over Mesoscale Domains, so CONUS-scale Fire Products (produced every 5 minutes) are shown instead. The Fire Temperature product in this case has a signal before an obvious signal is present in the 3.9 µm signal — although that could be a function of the 3.9 µm enhancement used here.

An observant reader will notice that the pixels in the GOES-16 Fire Product do not align with the GOES-16 3.9 µm pixels. This is because of the double remapping in the GOES-16 ABI Bands that occurs at NESDIS before data are sent to AWIPS. The Baseline product is not doubly remapped at NESDIS. (This double remapping is being removed from the processing stream shortly).

GOES-16 ABI Shortwave Infrared imagery (3.9 µm), shown every minute, and the GOES-16 Fire Temperature Baseline Product, shown every 5 minutes, 1905-2014 UTC on 23 March 2018 (Click to animate)

This animation (from Pete Wolf, SOO in Jacksonville FL), shows a fast-moving fire in the Fire RGB a bit later.  The animation is from the CIRA Slider, similar to this link that shows an animation from 2045 UTC on 23 March to 0045 on 24 March.