A natural-color image captured the eruption of Volcan de Fuego as it occurred. Credit: NASA/Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra satellite.
One of Central American’s most active volcanos erupted on September 13th, 2012 prompting officials to evacuate 35,000 residents in Guatemala. The Volcan de Fuego, or Fire Volcano, began belching out ash at 10 a.m. local time with ash now falling up to 40 kilometers (25 miles) from the volcano. Residents within 20 kilometers (12 miles) of the volcano were being removed from the area in buses and cars.
According to the Coordinadora Nacional para la Reducción de Desastres (CONRED), the eruption included ash emissions to the west and a 500-meter (2,000-foot) long lava flow. CONRED also warned of pyroclastic flows that could descend the mountain in any direction.
This natural-color image captured the eruption just as it occurred, NASA said. The image was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra satellite.
Thursday’s eruption was the sixth of the year for this volcano and some officials said it may be the biggest.
The powerful windstorms that swept across the US last week was captured by several different satellites. This type of storm, called a derecho, moved from Illinois to the Mid-Atlantic states on June 29, and the movie from NOAA’s GOES-13 satellite shows the storms’ sudden expansion and speed. The storms left a more than 1,000-km (700-mile) trail of destruction across the Midwest and mid-Atlantic, cutting power to millions and killing thirteen people.
A derecho (pronounced “deh-REY-cho”) is not your average, ordinary local summer thunderstorm. These are widespread, long-lived but rare wind storms that are usually associated with a band of rapidly moving showers or thunderstorms. Damage from a derecho is usually in one direction along a relatively straight track. By definition an event is classified a derecho if the wind damage swath extends more than 400 km (240 miles) and includes wind gusts of at least 93 km/h (58 mph) or greater along most of its length.
These storms occur in the United States during the late spring and summer, with more than three quarters occurring between April and August.
The movie begins on June 28 at 15:15 UTC (11:15 a.m. EDT) and ends on June 30, 2012 at 16:01 UTC (12:01 p.m. EDT). In the animation, the derecho’s clouds appear as a line in the upper Midwest on June 29 at 14:32. By 16:02 UTC, they appear as a rounded area south of Lake Michigan. By 21:32, the area of the derecho’s clouds were near Lake Erie and over Ohio expanding as the system track southeast. By 06:30 UTC, the size appears to have almost doubled as the derecho moves over West Virginia, Maryland, Pennsylvania and Virginia. At 02:32 UTC on June 30 (10:32 p.m. EDT), the Derecho was over the mid-Atlantic bringing a 160 km (100 mile) line of severe storms and wind gusts as high as 144 km/h (90 mph) to the region.
“It is interesting how the process is a self-sustaining process that is fed by a combination of atmospheric factors that all have to be in place at the same time,” said Joe Witte, a meteorologist in Climate Change Communication at George Mason University, Va. and a consultant to NASA. “That is why they are relatively rare: not all the elements line up that often.”
NASA’s Aqua satellite flew over the derecho on June 29 and June 30, using the Atmospheric Infrared Sounder instrument (AIRS) onboard to capture infrared imagery of the event, as seen above.
“The AIRS infrared image shows the high near-surface atmospheric temperatures blanketing the South and Midwestern U.S., approaching 98 degrees Fahrenheit,” said Ed Olsen of the AIRS Team at NASA’s Jet Propulsion Laboratory.
The AIRS images for June 30 show areas of intense convection centered off the New Jersey coast and another, less intense, system over Iowa-Indiana-Ohio. The area off the New Jersey coast is no longer a rapidly moving linear front. The near-surface atmospheric temperatures over the South and Midwest had decreased by 10 to 15 Fahrenheit in most areas,” Olsen said.
NASA’s Suomi National Polar-orbiting Partnership satellite (NPP) captured night-time images on June 28 and June 30, that reflected the massive blackouts that occurred after the derecho swept through the mid-Atlantic states. You can see the comparison images here at NASA’s Earth Observatory website.
The mechanics of a derecho go like this: The downburst mentioned by Witte, above, occurs when cold air in the upper atmosphere is cooled more by the evaporation of some of the rain and melting of the frozen precipitation pushed up into the high levels of the towering cumulonimbus (thunderclouds). That cold air becomes much denser than the surrounding air and literally falls to the ground, accelerating like any other falling body.
“The huge blob of very cold air from the upper atmosphere has a higher forward wind speed since it is high in the atmosphere,” Witte said. “This gives the ‘blob’ great forward momentum. Add that speed to the falling speed and the result is a very powerful forward moving surface wind.”
The process of a derecho can become self-sustaining as hot and humid air is forced upward by the gust front and develops more (reinforcing) towering clouds. If there is a rear low level jet stream, there is nothing to stop the repeating process.
It’s a wonder of nature, baby. Using information from data.gov, tech blogger John Nelson has created this spectacular image of tornado paths in the US over a 56 year period. The graphic categorizes the storms by F-scale with the brighter neon lines representing more violent storms.
Makes you want to hang on to something solid.
Nelson also provided some stats on all the storms in the different categories:
The numbers represent total deaths, total injuries, average miles the storms traveled
F0: 7, 267, 2
F1: 111, 3270, 6.58
F2: 363, 10373, 11.4
F3: 958, 18160, 17.80
F4: 1912, 28427, 28.62
F5: 1013, 11038, 38.87
This provides a new appreciation for the term “suck zone” used in the movie “Twister.”
While tornadoes don’t travel in straight lines, Nelson explains that based on the data, the vectors were created using touchdown points and liftoff points.
Nelson said he got the data from this Data.gov page doing a “tornado tracks” search.
If a portion of Earth underwent a major cataclysm, how long would it take for life to recover? The 1980 eruption of Mount St. Helens is giving scientists an unprecedented opportunity to witness a recovery from devastation, as the eruption leveled the surrounding forest, blasted away hundreds of meters of the mountain’s summit, and claimed 57 human lives. Landsat satellites have tracked the what has happened on the mountain, and how the forest was reclaimed — all on its own. This video shows a timelapse of the recovery, with annual images from 1979-2011 from the Landsat satellites, which acquired the images seen here between 1979 and 2011. Continue reading “Watch How Life Recovers from Devastation”
The 2012 tornado season got off to a rousing start. Between February 28th and March 3rd, two deadly storm systems developed in the southern United States. The storms spawned numerous tornadoes that together killed at least 52 people. This kind of extreme tornado activity, so early in the year, has fueled fears that global warming will increase the severity and duration of the tornado season. But, scientific studies show that this is not necessarily to be expected.
Early tornadoes are not unheard of. For example, on February 29 in 1952, two tornadoes caused severe damage in the south-eastern US. But this year, the number of early tornadoes has been much higher. The National Oceanic and Atmospheric Administration reported that in January of 2012, the tornado total was 95, much higher than the 1991–2010 average of 35. And the five-day total for February 28 to March 3 could rank as the highest ever since record-keeping began in 1950, according to meteorologist Dr. Jeff Masters, co-founder of the Weather Underground. With such a record-breaking start, it is not surprising people worry that a more severe 2012 storm season is ahead, and that global warming is to blame.
Tornadoes form when warm and moist air from the Gulf of Mexico meets with very cold and dry air above, which was brought south from the arctic. The collision of these air masses, which have different densities, as well as speeds and directions of motion, forces them to want to switch places very rapidly. This creates updrafts of warm and wet air, which produce thunderstorms. And, as the updrafts climb through the atmosphere, they encounter fast- moving jet stream winds, which change speed and direction with altitude. These changes give the updraft a strong twisting motion that spawns tornadoes.
The severity of tornadoes is rated on the Fujita Scale, which examines how much damage is left after a tornado has passed: F0-F1 tornadoes produce minor damage and so are considered weak, F2-F3 tornadoes produce significant damage and are considered strong, and F4-F5 tornadoes produce severe damage and are considered violent. The problem with this ranking is that it is related to a human-based assessment of damage; you need something (buildings, vegetation, etc.) to be destroyed and someone to see the damage. So, a severe tornado that occurs somewhere where there is nothing to be destroyed would be classed as weak, and one that occurs where there is no-one to see the damage wouldn’t even be counted.
Still, tornado awareness and volunteer reporting programs, along with good record-keeping, have significantly improved our understanding of tornadoes and their frequency. Surprisingly, the Storm Prediction Center’s tornado database, which goes back to 1950, does not show an increasing trend in recent tornadoes. This finding is confirmed by Dr. Stanley Changnon from the University of Illinois at Urbana-Champaign, whose study of insurance industry records was published last year. Dr. Changnon’s work shows that tornado catastrophes and their losses peaked in the years between 1966 and 1973, but have shown no upward trend since that time. In fact, the number of the most damaging storms, those rated as F2 to F5 has actually decreased over the past 5 decades. So, it does not appear that global warming is increasing the number of tornadoes that occur.
This is actually not as surprising as it seems. While a local increase in temperature and humidity, whether caused by global warming or not, would be expected to create more thunderstorms, it is not clear that these thunderstorms would spawn tornadoes. The reason is that global warming does not increase temperatures the same everywhere. Warming at the poles is expected to exceed warming at more southern latitudes. This means that cold polar air will be much less colder than before and warm Gulf of Mexico air will only be slightly warmer. When these two air masses meet above the southern US, the temperature difference between them will not be so great and their drive to swap places will be much less intense. The result will be a significantly slower moving updraft of warm air that is not expected to produce as many extreme thunderstorms or spawn as many tornadoes.
So, global warming is not expected to increase the total frequency of tornado activity. However, warming global temperatures will mean an earlier spring and the potential for earlier tornadoes. In fact, the early tornado numbers we’ve seen so far this year may be a sign of a global warming-induced shift in the tornado season, according to Dr. Masters. If this is the case, the tornado season may start earlier, but it will also end earlier. As meteorologist Harold Brooks from the National Severe Storms Laboratory in Norman, Oklahoma, points out, this record start to the 2012 tornado season does not necessarily mean the rest of the season will be severe.
Recap of deadly U.S. tornado outbreak February 28-March 3, 2012, M. Daniel, EarthSky Mar 5, 2012.
NASA Earth Observatory, March 5, 2012.
Temporal distribution of weather catastrophes in the USA, S.A. Changnon, Climatic Change 106 (2), 129-140, 2011, doi: 10.1007/s10584-010-9927-1.
Does Global Warming Influence Tornado Activity? Diffenbaugh et al., EOS 89 (53), 553-554, 2008.
What a view: Here’s a video of Hurricane Irene’s path, starting on August 24 up until 18:40 UTC on August 26, 2011, as seen by a GOES satellite. Even though Hurricane Irene is continuing to slowly weaken as it pushes closer to the Carolina coast, this massive storm could affect a huge area of the Eastern US seaboard, and tropical storm force winds and squalls are buffeting the coast. Irene will impact the entire Mid-Atlantic and Northeast Coast, including Washington, Philadelphia, New York City, Hartford, Ct. and Boston this weekend.
This hurricane spans nearly 1,000 kilometers (600 miles).
Below is a video taken from the International Space Station late yesterday afternoon. Includes astronaut commentary on the view of this “huge, scary storm” from 370 km (230 miles) up:
Cameras mounted on the International Space Station captured this video. Forecasters are predicting landfall on the outer banks of North Carolina Saturday before tracking up the mid-Atlantic states and a possible path over the metropolitan New York area and New England late this weekend.
Hot off the wires is this satellite image of Hurricane Irene taken less than an hour ago (as of this writing) by one of the GOES satellites for NOAA.
Here are several different views of Hurricane Irene: from 230 miles above the Earth, cameras on the International Space Station captured several views of powerful Hurricane Irene as it churned over the Bahamas at 3:10 p.m. EDT on August 24, 2011. Irene is moving to the northwest as a Category 3 hurricane, packing winds of 120 miles an hour. Irene is expected to strengthen to a Category 4 storm as it heads toward the Outer Banks of North Carolina, the Eastern Seaboard and the middle Atlantic and New England states.
See more from other satellites, below:
This view of Irene was taken by the GOES satellite at 2:55 p.m. Eastern Daylight Time on August 24, 2011. Irene now has a distinct eye and the clouds spiraling around the center are becoming more compact. The image also shows how large Irene has become, measuring several hundred kilometers across.
This image was taken on August 22, but is a really nifty, three-dimensional view of the precipitation from Irene, as seen by the Tropical Rainfall Measuring Mission. It reveals an area of deep convection (shown in red) near the storm’s center where precipitation-sized particles are being carried aloft. These tall towers are associated with strong thunderstorms responsible for the area of intense rain near the center of Irene seen in the previous image. They can be a precursor to strengthening as they indicate areas within a storm where vast amounts of heat are being released. This heating, known as latent heating, is what is drives a storm’s circulation and intensification.
As of 8 a.m. EDT on August 25, Hurricane Irene was located near 25.5 N and 76.5 W, or 65 miles east-southeast of Nassau, Bahamas. This places it about 670 miles south of Cape Hatteras, N.C. Irene`s top sustained winds remain at 115 mph, and is moving to the northwest at 13 mph.
Wow! What an amazing and detailed top-down view of an active volcano! This is the Nabro Volcano, which has been erupting since June 12, 2011. It sits in an isolated region on the border between Eritrea and Ethiopia and satellite remote sensing is currently the only reliable way to monitor the ongoing eruption, according to the NASA Earth Observatory website. The bright red portions of the false-color image (above) indicate hot surfaces. See below for a zoomed-in look. Both images were taken by the Advanced Land Imager (ALI) aboard the Earth Observing-1 (EO-1) satellite.
Robert Simmon of the NASA Earth Observatory website describes the scenes:
Hot volcanic ash glows above the vent, located in the center of Nabro’s caldera. To the west of the vent, portions of an active lava flow (particularly the front of the flow) are also hot. The speckled pattern on upstream portions of the flow are likely due to the cool, hardened crust splitting and exposing fluid lava as the flow advances. The bulbous blue-white cloud near the vent is likely composed largely of escaping water vapor that condensed as the plume rose and cooled. The whispy, cyan clouds above the lava flow are evidence of degassing from the lava.
The natural-color image (lower) shows a close-up view of the volcanic plume and eruption site. A dark ash plume rises directly above the vent, and a short, inactive (cool) lava flow partially fills the crater to the north. A gas plume, rich in water and sulfur dioxide (which contributes a blue tint to the edges of the plume) obscures the upper reaches of the active lava flow. Black ash covers the landscape south and west of Nabro.
Limited reports from the region say that at least 3,500 people and up to 9,000 that have been affected by the eruption, with at least 7 deaths caused by the erupting volcano. The ash plume has also disrupted flights in the region.
An incredible amount of ash is being spewed from the erupting Puyehue-Cordón Volcano Complex in Chile. This image, taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite on June 13, 2011, shows a large plume of volcanic ash blowing about 780 kilometers east and then northeast over Argentina. A plume of volcanic ash from this eruption disrupted air traffic as far away as New Zealand on June 13. See images below of how far the ash has traveled in the atmosphere, a half a world away.
The Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite acquired the two images below of the Chilean ash plume on June 13, 2011 showing that a concentrated plume was visible more than half a world away. The first image shows the ash plume over southern Australia and the Tasman Sea, while the second image provides a view farther east over New Zealand and the South Pacific Ocean.
NASA’s Earth Observatory website says that although the intensity of the eruption has decreased since the initial eruption, the volcano’s activity is holding steady. The plume reached between 4 and 8 kilometers in altitude on June 13, its height varying with the intensity of the eruptive episode throughout the day.
Here’s how the volcano looked back on June 4, 2011 when it began spewing ash 45,000 feet (14,000 meters) into the air. The Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite captured this natural-color image shortly after the eruption began:
This video from NOAA’s GOES geostationary satellite shows the development of the supercell storm that produced the devastating tornado that struck Joplin, Missouri. Here you can see the storm develop over Missouri, Oklahoma, Kansas state lines on May 22, 2011 between 12:44pm to 7:15pm CDT. This was part of the great wave of severe storms that swept across the central United States, with tornado warnings from Minneapolis to Dallas. The most damaging storm struck Joplin at 5:30 pm local time (2230 UTC), killing at least 116 people.