Fire following a train derailment and crash in North Dakota

December 30th, 2013 |

GOES-13 0.63 µm visible channel (left) and 3.9 µm shortwave IR channel (right) images [click to play animation]

GOES-13 0.63 µm visible channel (left) and 3.9 µm shortwave IR channel (right) images [click to play animation]

A train derailment occurred about one mile west of Casselton, North Dakota at 20:10 UTC (2:10 PM local time) on 30 December 2013 — ten cars of a westbound train transporting grain initially derailed, which then caused an eastbound train transporting crude oil to also derail. A large fire and multiple explosions erupted from the engine and 18 cars of the derailed eastbound train, which were carrying crude oil from the Bakken oil shale field region in northwestern North Dakota. McIDAS images of GOES-13 0.63 µm visible channel and 3.9 µm shortwave IR data (above; click image to play animation; also available as a QuickTime movie) showed the dark smoke plume beginning with the 20:15 UTC visible image, which then quickly fanned out to the south-southeast by 21:45 UTC. On the corresponding shortwave IR images, a darker gray fire “hot spot” accompanied the initial visible image signature of the smoke plume at 20:15 UTC, which later became very hot (dark black) on the 21:15 UTC image.

A comparison of GOES-15 (GOES-West, positioned at 135º West longitude) and GOES-13 (GOES-East, positioned at 75º West longitude) 0.63 µm visible channel images (below; click image to play animation) showed how the dark smoke plume appeared from the very different viewing perspectives of the two geostationary satellites. On both sets of images the eastern portion of the smoke plume appeared to have drifted over Interstate 29 (I-29) south of Fargo (FAR), but due to the low sun angle it is likely that this was actually the shadow from the dark smoke plume. Note that the low cloud features cast similar shadows during the late afternoon hours toward the end of the animation.

GOES-15 (left) vs GOES-13 (right) 0.63 µm visible channel images [click to play animation]

GOES-15 (left) vs GOES-13 (right) 0.63 µm visible channel images [click to play animation]

The corresponding comparison of GOES-15 vs GOES-13 3.9 µm shortwave IR images (below; click image to play animation) also showed differences in the apparent intensity of the fire hot spot, which were dependent upon satellite viewing angle, viewing time, and the opacity of the dense smoke plume overhead. On the GOES-13 21:15 UTC image (which was actually scanning the fire area at 21:17 UTC), a notable increase in IR brightness temperature was seen, with the hot spot exhibiting a brightness temperature of 322 K (48.9º C or 120º F). This was likely the near the time of one of several explosions (video 1 | video 2). GOES-15 was not scanning the fire area at that particular time, so a fire hot spot of that intensity was not evident in the imagery.

GOES-15 (left) and GOES-13 (right) 3.9 µm shortwave IR images [click to play animation]

GOES-15 (left) and GOES-13 (right) 3.9 µm shortwave IR images [click to play animation]

===== 31 December Update =====

The intense oil-fueled fire continued to burn into the following night; an AWIPS image of Suomi NPP VIIRS 0.7 µm Day/Night Band (DNB) data at 09:07 UTC or 3:07 AM local time on 31 December (below) showed the bright glow of the fire near Casselton, as well as the smoke plume which was still drifting to the southeast. The glow of lights from cities and towns appeared somewhat blurry on the DNB image, due to scattering of the light through a thin veil of cirrus clouds that was drifting over the region (VIIRS 11.45 µm IR channel image). Since the Moon was nearly in the New phase, there was very little moonlight to illuminate the smoke plume — airglow and lights from nearby cities and towns helped to make this feature visible on the DNB image. Note that the navigation of the DNB image was slightly off, with the image being shifted a few miles to the southwest; in addition, this particular DNB image was enhanced to provide a darker contrast, eliminating “noise” from the glow of the regional snow cover (which was generally in the 5-13 inch range) to help highlight the smoke plume. A subtle signature of the fire hot spot (a darker gray pixel) could still seen on the corresponding VIIRS 3.74 µm shortwave IR image.

Suomi NPP VIIRS 0.7 µm Day/Night Band image

Suomi NPP VIIRS 0.7 µm Day/Night Band image

Due to air quality concerns from the toxic smoke plume, residents immediately downwind of the crash site were urged to evacuate. At Fargo’s Hector International Airport (located about 25 miles to the east of Casselton), the surface visibility dropped to 2 miles with haze at 06:53 UTC (12:53 AM local time) on 31 December, as winds shifted to the southwest (time series of surface reports); it is unknown whether this drop in visibility was due to smoke being transported from the accident site, or simply from local sources (such as the widespread burning of firewood in the city, given that the ambient air temperature at the time was -15º F). A WDAY News tower camera photo (below) showed that the dark smoke plume could be seen from downtown Fargo — the tower camera is looking to the west, and the smoke plume is drifting southward (to the left).

WDAY News tower camera photo, looking west from downtown Fargo

WDAY News tower camera photo, looking west from downtown Fargo

Aircraft distrails and contrails

December 30th, 2013 |
Suomi NPP VIIRS 0.64 µm visible channel and false-color RGB images

Suomi NPP VIIRS 0.64 µm visible channel and false-color RGB images

Two signatures of aircraft traffic sometimes seen in satellite imagery are (1) dissipation trails, or “distrails”, and (2) condensation trails, or “contrails”. On 30 December 2013, examples of both were seen over Virginia and West Virgina. Multiple layers of clouds existed over the region as a cold frontal boundary was moving eastward; ahead of the cold front patchy areas of low-level supercooled water droplet clouds were drifting northeastward across North Carolina and Virginia, and examples of aircraft distrails could be seen in a comparison of Suomi NPP VIIRS 0.64 µm visible channel and false-color Red/Green/Blue (RGB) images at 17:29 UTC (above). When aircraft penetrated the supercooled water droplet cloud deck, particles in their exhaust acted as ice condensation nuclei which then created narrow lines of glaciated (ice) clouds in their wake. One particularly vivid example of a distrail was oriented from southwest to northeast over central Virginia. Ice clouds appeared as varying shades of red in the RGB image, in contrast to supercooled water droplet clouds which showed up as brighter white features.

Farther to the west, a wide band of higher-altitude ice clouds existed as part of an elongated warm conveyor belt that was approaching the East Coast of the US. A comparison of Suomi NPP VIIRS 3.74 µm shortwave IR channel and 11.45 µm IR channel images at 17:29 UTC (below) revealed the presence of widespread contrails over much of West Virginia into western Virginia. The contrails were nearly as cold as the underlying high-altitude cirrus clouds on the 11.45 µm IR image, making their identification more difficult — however, the contrails were quite evident on the shortwave IR image, since their smaller particles were very efficient reflectors of solar radiation (making them exhibit a warmer, darker gray signature).

Suomi NPP VIIRS 3.74 µm shortwave IR and 11.45 µm IR channel images

Suomi NPP VIIRS 3.74 µm shortwave IR and 11.45 µm IR channel images

Other examples of aircraft distrails can be found in previous blog posts.

Low-level “barrier jet” along the southeast coast of Greenland

December 29th, 2013 |
GOES-13 6.5 µm water vapor images with Metop ASCAT scatterometer winds and surface METARs and surface analyses (click to play animation)

GOES-13 6.5 µm water vapor images with Metop ASCAT scatterometer winds and surface METARs and surface analyses (click to play animation)

AWIPS images of GOES-13 6.5 µm water vapor channel data with available overpasses of Metop ASCAT surface scatterometer winds (above; click image to play animation) revealed the presence of a low-level “barrier jet” along the southeast coast of Greenland on 29 December 2013. Maximum ASCAT wind speeds were 58 knots at 12:16 UTC, 62 knots at 13:57 UTC, and 62 knots at 22:09 UTC. It is interesting to note that a secondary area of low pressure was seen rotating around the primary low, and appeared to be rapidly intensifying judging from the quick development of a “corkscrew” appearance on the water vapor imagery near the end of the animation. ASCAT winds along the northwestern periphery of this secondary low were as high as 53 knots at 22:09 UTC.

The cyclonic circulation around the quasi-stationary area of low pressure located east of Greenland encountered the abrupt rise in topography of the island (below), which caused an acceleration of the flow known as a “barrier jet”.

Topography of Greenland, with Metop ASCAT scatterometer winds and surface METAR reports and surface analysis

Topography of Greenland, with Metop ASCAT scatterometer winds and surface METAR reports and surface analysis

Chaparrastique erupts in El Salvador

December 29th, 2013 |
GOES-13 0.63 µm visible imagery during Chaparrastique eruption (click to play animation)

GOES-13 0.63 µm visible imagery during Chaparrastique eruption (click to play animation)

The volcano Chapparastique in eastern El Salvador near the city of San Miguel experienced a brief eruption on Sunday the 29th of December (YouTube video). Half-hourly 0.63 µm visible channel imagery from GOES-13 or GOES-East (the most frequent imagery available at 13.5º N, the latitude of the volcano), above, plainly shows the appearance of the volcanic ash cloud between 16:15 and 16:45 UTC (media sources reported that the time of the eruption was 16:32 UTC). Most of the ash cloud then moved westward across the coast and over the adjacent waters of the Pacific Ocean, although parts of the ash cloud also moved eastward over Honduras. This is the first complete Chapparastique advisory from the VAAC in Washington DC on this eruption. The most recent volcanic ash advisories can be found here.

GOES-15 or GOES-West, positioned at 135º W, was also able to view the ash cloud, and that animation is below. El Salvador is near the eastern edge of the satellite view. Routine scanning that was taking place on Sunday 29 December only viewed El Salvador every three hours.

GOES-15 0.63 µm visible imagery during Chaparrastique eruption (click to play animation)

GOES-15 0.63 µm visible imagery during Chaparrastique eruption (click to play animation)

It happens occasionally that useful information about volcanic eruptions can be gleaned from extreme limb views from geostationary satellites (see here, for example, or this animation from this blog post). In the present case, the MTSAT-2 visible imagery, below, was a bit too far to the west to view the atmosphere over central America.

MTSAT-2 0.73 µm visible imagery during Chaparrastique eruption (click to play animation)

MTSAT-2 0.73 µm visible imagery during Chaparrastique eruption (click to play animation)

Meteosat-10 data possibly saw the eruption; however, the remapped imagery that is broadcast does not include pixels for which a latitude/longitude value can be computed, such as pixels that are at the extreme edge of the limb, in outer space. To ascertain the presence of a signal in the satellite data would require access to the raw data from the satellite, and that is not routinely available. Meteorsat-10 visible images surrounding the eruption time are shown below.

METEOSAT-10 0.6 µm visible imagery during Chaparrastique eruption (click to play animation)

METEOSAT-10 0.6 µm visible imagery during Chaparrastique eruption (click to play animation)

Note that when GOES-R ABI is broadcasting data, its limb edge will resemble the METEOSAT-10 data above rather than the more complete MTSAT-2 data. Level 0 data from ABI includes space looks at the limb; that level 0 data will be calibrated, navigated and remapped and distributed as level 1 GOES-R series ReBroadcast (GRB) data that will not include points at the limb that are un-navigable (but that nevertheless can include interesting data).

As part of CIMSS/ASPB participation in GOES-R Proving Ground activities, various volcanic ash detection and analysis products have been developed. Below is an animation of GOES-13 multi-spectral false-color Red/Green/Blue (RGB) images that also show the dispersion of the volcanic ash cloud.

GOES-13 multi-spectral RGB images (click to play animation)

GOES-13 multi-spectral RGB images (click to play animation)

Examples of some of the quantitative volcanic ash products are shown below, using MODIS data from an overpass of the Aqua satellite at 18:50 UTC. The maximum ash height appeared to be around 10 km along the eastern end of the cloud; the maximum ash loading approached 6 g/m2 on the western edge of the plume; the maximum ash particle effective radius was in the 14-16 µm range along the edges of the cloud.

Aqua MODIS Ash/Dust Cloud Height product

Aqua MODIS Ash/Dust Cloud Height product

Aqua MODIS Ash/Dust Loading product

Aqua MODIS Ash/Dust Loading product

Aqua MODIS Dust/Ash Particle Effective Radius product

Aqua MODIS Dust/Ash Particle Effective Radius product