Eruption of the Mount Pavlof volcano in Alaska

March 28th, 2016

Himawari-8 AHI Shortwave Infrared (3.9 µm) images [click to play animation]

Himawari-8 AHI Shortwave Infrared (3.9 µm) images [click to play animation]

A major eruption of the Mount Pavlof volcano on the Alaska Peninsula began shortly before 0000 UTC on 28 March, or 4:00 pm on 27 March Alaska time (AVO report), as detected by a thermal anomaly (or “hot spot”, yellow to red color enhancement) on Himawari-8 AHI Shortwave Infrared (3.9 µm) images (above). The hot spot decreased in size and intensity toward the later hours of the day, signaling a lull in the volcanic eruption.

It is interesting to note on a comparison of the 0000 UTC Himawari-8 and GOES-15 Shortwave Infrared (3.9 um) images the large difference in the magnitude of the thermal anomaly — even though the viewing angle was larger for Himawari-8, the superior spatial resolution (2 km at nadir, compared to 4 km with GOES-15) detected a hot spot with an Infrared Brightness Temperature (IR BT) that was 36.6 K warmer (below). The Infrared channels on the GOES-R ABI instrument will also have a 2 km spatial resolution.

Himawari-8 AHI (left) and GOES-15 Imager (right) 3.9 µm Shortwave Infrared images [click to enlarge]

Himawari-8 AHI (left) and GOES-15 Imager (right) 3.9 µm Shortwave Infrared images [click to enlarge]

With the aid of reflected light from the Moon (in the Waxing Gibbous phase, at 75% of Full), a nighttime view using the Suomi NPP VIIRS Day/Night Band (0.7 µm) from the SSEC RealEarth site (below) revealed the bright glow of the eruption, along with the darker (compared to adjacent meteorological clouds) volcanic ash cloud streaming northeastward. The corresponding VIIRS Shortwave Infrared (3.74 µm) image showed the dark black hot spot of the volcano summit.

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) and Day/Night Band (0.7 µm) image [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) and Day/Night Band (0.7 µm) image [click to enlarge]

The volcanic ash cloud continued moving in a northeastward direction, as seen in a sequence of GOES-15 Infrared Window (10.7 µm) and either Terra/Aqua MODIS or Suomi NPP VIIRS retrieved Volcanic Ash Height products from the NOAA/CIMSS Volcanic Could Monitoring site (below).

GOES-15 Infrared (10.7 µm) images, with Terra/Aqua MODIS and Suomi NPP VIIRS Ash Height products [click to play animation]

GOES-15 Infrared (10.7 µm) images, with Terra/Aqua MODIS and Suomi NPP VIIRS Ash Height products [click to play animation]

Due to the oblique satellite view angle, the shadow cast by the tall volcanic ash cloud was easily seen on the following early morning (Alaska time) Himawari-8 AHI Visible (0.64 µm) images (below). A closer view (courtesy of Dan Lindsey, RAMMB/CIRA) revealed overshooting tops and gravity waves propagating downwind of the eruption site.

Himawari-8 AHI Visible (0.64 um) images (click to play animation]

Himawari-8 AHI Visible (0.64 um) images (click to play animation]

A few select Pilot reports (PIREPs) are shown below, plotted on GOES-15 Infrared Window (10.7 µm) and Aqua MODIS Ash Height derived products. Numerous flights were canceled as the ash cloud eventually began to drift over Western and Interior Alaska (media report).

GOES-15 Infrared Window (10.7 um) image, with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 µm) image, with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 um) image, with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 µm) image, with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 um) image, with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 µm) image, with METAR surface reports and Pilot reports [click to enlarge]

Aqua MODIS Ash Height product, with METAR surface reports and Pilot reports [click to enlarge]

Aqua MODIS Ash Height product, with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 um), with METAR surface reports and Pilot reports [click to enlarge]

GOES-15 Infrared Window (10.7 µm), with METAR surface reports and Pilot reports [click to enlarge]

A comparison of Suomi NPP VIIRS Shortwave Infrared (3.74 µm), Day/Night Band (0.7 µm), and true-color Red/Green/Blue (RGB) images (below) showed the volcanic hot spot and the brown to tan colored ash cloud at 2141 UTC on 28 March. Significant ash fall (as much as 2/3 of an inch) was experienced at the village of Nelson Lagoon, located 55 miles northeast of Pavlof (media report).

Suomi NPP VIIRS Shortwave Infrared (3.74 µm), Day/Night Band (0.7 µm), and true-color RGB images [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.74 µm), Day/Night Band (0.7 µm), and true-color RGB images [click to enlarge]

A comparison of the 3 Himawari-8 AHI Water Vapor bands (7.3 µm, 6.9 µm and 6.2 µm) covering the first 14 hours of the eruption from 0000 to 1400 UTC is shown below. Note that the volcanic plume was best seen on the 7.3 µm images, which indicated that it began to move over the coast of Western Alaska after around 0600 UTC; this is due to the fact that the 7.3 µm band is not only a “water vapor absorption” band, but is also sensitive to high levels of SO2 loading in the atmosphere (as was pointed out in this blog post).

Himawari-8 AHI Water Vapor 7.3 µm (left), 6.9 µm (center) and 6.2 µm (right) images [click to play animation]

Himawari-8 AHI Water Vapor 7.3 µm (left), 6.9 µm (center) and 6.2 µm (right) images [click to play animation]

Large grass fire in Oklahoma and Kansas

March 23rd, 2016

GOES-13 Shortwave Infrared (3.9 µm) images, with surface reports [click to play animation]

GOES-13 Shortwave Infrared (3.9 µm) images, with surface reports [click to play animation]

A grass fire (now referred to as the “Anderson Creek fire”) was first reported in western Woods County, Oklahoma around 2245 UTC or 5:45 PM local time on 22 March 2016. “Hot spot” signatures (yellow to red to black pixels) on GOES-13 Shortwave Infrared (3.9 µm) images (above) showed that the fire proceeded to make a very fast run to the north during the overnight hours, crossing over the Kansas border into Comanche and Barber Counties. The fire eventually jumped Highway 160  — which runs west-to-east across the northern portion of those 2 counties (highways are plotted in violet) — forcing it to be closed for several hours. As of the afternoon of 23 March, the fire was reported to have burned at least 72,000 acres; on that evening, the mayor of Medicine Lodge, Kansas (station identifier KP28) called for a voluntary evacuation as the fire began to approach the edge of the town. Note that GOES-13 (GOES-East) had been placed into Rapid Scan Operations (RSO) mode specifically to monitor the extremely critical fire risk, and was providing images as frequently as every 5-7 minutes.

A nighttime comparison of Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images at 0823 UTC or 3:23 AM local time (below) showed the hot spots and the bright glow of the large and very hot fire.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images {click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images {click to enlarge]

A sequence of Shortwave Infrared images from POES AVHRR, Terra/Aqua MODIS, and Suomi NPP VIIRS (below) provided higher-resolution snapshots of the rapid northward progression of the fire during the overnight hours (aided by strong southerly winds), followed by an east/northeastward expansion during the subsequent daylight hours (driven by a switch to strong southwesterly winds after the passage of a dryline).

POES AVHRR (3.7 µm), Terra/Aqua MODIS (3.7 µm), and Suomi NPP VIIRS (3.74 µm) Shortwave Infrared images [click to enlarge]

POES AVHRR (3.7 µm), Terra/Aqua MODIS (3.7 µm), and Suomi NPP VIIRS (3.74 µm) Shortwave Infrared images [click to enlarge]

GOES-13 Visible (0.63 µm) images (below) revealed a large increase in smoke produced by the fire during the day on 23 March. This smoke was drawn cyclonically northeastward then northward around the circulation of a storm system that was deepening over western Kansas. Afternoon wind gusts were as high as 61 mph in Newton, Kansas. Downstream of the fire source region, smoke reduced the surface visibility to 4 miles at Hutchinson, Kansas (station identifier KHUT) at 21 UTC or 4 PM local time, and Wichita (station identifier KICT) reported a visibility of 1.75 miles at 00 UTC or 7 PM local time; ash falling from the smoke aloft caused the surface air quality in Wichita to briefly deteriorate to unhealthy levels.

GOES-13 Visible (0.63 µm) images, with surface reports [click to play animation]

GOES-13 Visible (0.63 µm) images, with surface reports [click to play animation]

In the early afternoon at 1748 UTC or 12:48 PM local time, a pilot report near the northern flank of the fire (below) indicated that the tops of the smoke towers were already rising to altitudes of 8000 to 11000 feet above ground level.

GOES-13 Visible (0.63 µm) image, with surface reports and a pilot report of smoke altitude [click to enlarge]

GOES-13 Visible (0.63 µm) image, with surface reports and a pilot report of smoke altitude [click to enlarge]

It is of interest to note that a similar (albeit smaller) grass fire spread rapidly northward from Oklahoma into Kansas, one county to the west and about one month earlier: the Buffalo fire. That event had the benefit of Super Rapid Scan Operations of GOES-14, which provided imagery at 1-minute intervals. The ABI instrument on the GOES-R satellite will be capable of providing 1-minute images over 2 pre-defined mesoscale sectors.

===== 24 March Update =====

Anderson Creek Fire perimeter map [click to enlarge]

Anderson Creek Fire perimeter map [click to enlarge]

A map of the Anderson Creek Fire perimeter (above) was issued by the Oklahoma Forestry Services at 1642 UTC or 11:42 AM local time. At that time, an estimated 397,420 acres (621 square miles) had been burned — which makes it the largest wildfire on record for the state of Kansas.

A comparison of Suomi NPP VIIRS true-color and false-color Red/Green/Blue (RGB) images from the SSEC RealEarth site (below) showed the extent of the burn scar, with smoke plumes drifting south-southeastward from 2 small areas of fires that were still actively burning at 2106 UTC or 4:06 PM local time. As discussed above, it can be seen that the fire crossed (and forced the closure of) US Highway 160 between Coldwater and Medicine lodge, and came very close to the town of Medicine Lodge.

Suomi NPP VIIRS true-color and false-color images [click to enlarge]

Suomi NPP VIIRS true-color and false-color images [click to enlarge]

===== 25 March Update =====

Suomi NPP VIIRS Day/Night Band (0.7 µm) image [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) image [click to enlarge]

With ample illumination from the Moon (in the Waning Gibbous phase, at 98% of Full), the contrast between the dark Anderson Creek fire burn scar and the lighter surrounding grassland was very apparent on a Suomi NPP VIIRS Day/Night Band (0.7 µm) image at 0742 UTC or 2:42 AM local time. This example demonstrates the “visible image at night” capability of the VIIRS Day/Night Band.

Strong storm over the Upper Midwest and western Great Lakes

March 16th, 2016

GOES-13 Water Vapor (6.5 µm) images, with surface analyses [click to play animation]

GOES-13 Water Vapor (6.5 µm) images, with surface analyses [click to play animation]

A strong storm rapidly deepened as it moved northeastward across the Upper Midwest and western Great Lakes on 16 March 2016. GOES-13 Water Vapor (6.5 µm) images (above) showed the evolution of the system as the cloud shield expanded and became more elongated in a west-to-east orientation. On the previous day, this storm produced widespread hail and tornadoes from far eastern Iowa into northern and central Illinois (SPC storm reports).

A closer view of GOES-13 Visible (0.63 µm) images with METAR surface reports (below) revealed the strong winds caused by the tight pressure gradient — a peak wind gust of 61 mph was recorded at Waukesha in southeastern Wisconsin, with multiple power outages across the region caused by wind-related tree damage. Heavy rain (as much as 2-3 inches) produced some minor river flooding in various parts of Wisconsin; across northern Wisconsin, northeastern Minnesota, and the Upper Peninsula of Michigan the rain changed to snow, with as much as 18.5 inches accumulating at Redridge, Michigan, 13.0 inches at Lutsen, Minnesota, and 8.0 inches at Poplar and Sand Bay, Wisconsin. The weight of the wet snow was causing tree limbs to fall, with additional power outages being reported.

GOES-13 Visible (0.63 µm) images [click to play animation]

GOES-13 Visible (0.63 µm) images [click to play animation]

With the strong winds associated with this storm, there were also scattered pilot reports of moderate turbulence across the region, including 2 reports of severe turbulence over southern Wisconsin as seen below.

GOES-13 Water Vapor (6.5 µm) image, with pilot report of severe turbulence [click to enlarge]

GOES-13 Water Vapor (6.5 µm) image, with METAR surface reports and a pilot report of severe turbulence [click to enlarge]

GOES-13 Water Vapor image, with pilot report of severe turbulence [click to enlarge]

GOES-13 Water Vapor image, with METAR surface reports and a pilot report of severe turbulence [click to enlarge]

Moderate to severe turbulence over the Midwest

March 11th, 2016

GOES-13 Water Vapor (6.7 µm) images with Pilot Reports of turbulence [click to play animation]

GOES-13 Water Vapor (6.7 µm) images with Pilot Reports of turbulence [click to play animation]

There were numerous pilot reports of Moderate to Severe turbulence (symbols) over much of the Midwest on 11 March 2016, as shown plotted on 4-km resolution GOES-13 (GOES-East) Water Vapor (6.5 µm) images (above). A packet of transverse banding cloud features developed over eastern Kansas after about 1515 UTC, and moved northeastward over northwestern Missouri/southeastern Nebraska/Iowa/northern Illinois/southern Wisconsin during the day.

The transverse banding cloud filaments showed up with a bit more clarity on a 1-km resolution Aqua MODIS Water Vapor (6.7 µm) image at 1919 UTC (below).

Aqua MODIS Water Vapor (6.7 µm) image [click to enlarge]

Aqua MODIS Water Vapor (6.7 µm) image [click to enlarge]

A MODIS Cirrus (1.4 µm) image at 1738 UTC (below) was also a very effective tool for helping to visualize the transverse banding cloud filaments. A Turbulence SIGMET had been issued at 1433 UTC for much of the region, due to wind shear associated with jet steam aloft. Many of the pilot reports were noted to be Clear Air Turbulence (CAT), with one describing the severe turbulence encounter as “one jolt“. It can be seen from the GFS model isotachs of Maximum Wind that the reports of turbulence occurred within the entrance region of a curved jet stream segment, which are areas that favor the development of strong vertical and horizontal wind shear responsible for turbulence.

 Terra MODIS "Cirrus" (1.38 µm) image with Turbulence SIGMET, Pilot Reports of turbulence, and GFS Max Wind isotachs [click to enlarge]

Terra MODIS “Cirrus” (1.38 µm) image with Turbulence SIGMET, Pilot Reports of turbulence, and GFS Max Wind isotachs [click to enlarge]

On a comparison of 1-km resolution Aqua MODIS Visible (0.65 µm) and Infrared Window (11.0 µm) images at 1919 UTC (below), the very thin nature of the transverse banding cirrus cloud features made them difficult to identify on the Visible image; they also exhibited very warm Infrared brightness temperature values (around -15º C) due to the fact that the satellite was also sensing a good deal of warm thermal radiation from the ground surface below the thin cirrus. As seen in the previous example above, the transverse banding high cloud filaments showed up very well on the MODIS 1.38 µm Cirrus image. Imagery from this 1.38 µm spectral band will also be available from the ABI instrument on GOES-R.

Aqua MODIS Visible (0.65 µm), Infrared Window (11.0 µm), and Cirrus (1.38 µm) images, with Pilot Reports of turbulence [click to enlarge]

Aqua MODIS Visible (0.65 µm), Infrared Window (11.0 µm), and Cirrus (1.38 µm) images, with Pilot Reports of turbulence [click to enlarge]

Hat tip to Scott Dennstaedt for the heads-up on this event: