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Earth Matters

Responding to Hurricane Florence with NASA Data

September 21st, 2018 by Kasha Patel

Early on September 12, 2018, astronaut Alex Gerst shot this photograph of Florence’s eye as viewed from the International Space Station. He tweeted: “Ever stared down the gaping eye of a category 4 hurricane? It’s chilling, even from space.” Credit: ISS Photograph by Alex Gerst, European Space Agency/NASA

When Hurricane Florence approached the Carolinas, the NASA Disasters Program began providing a suite of satellite data products to disaster responders, such as the Federal Emergency Management Agency (FEMA) and the National Guard. The goal was to provide the latest information for decision-making on everything from evacuations to supply routes to recovery estimates.

Andrew Molthan is a research meteorologist at NASA’s Marshall Space Flight Center who serves as a “disaster coordinator” for the disasters program. This week, he has been sitting at the FEMA National Response Coordination Center in Washington, D.C., to facilitate coordination of NASA data. We asked him a few questions to better understand the NASA Disaster Program’s role during Hurricane Florence.

What is your role at FEMA this week?

I am here at FEMA to better understand the agency’s geospatial needs during a major disaster, to help improve coordination, and to lend additional remote sensing and/or meteorological expertise where I can.

I am also helping with coordination and data exploitation for the Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) instrument aboard NASA’s C-20A aircraft, operated by a pilot. As a team, colleagues from NASA centers all over the country—Marshall, Headquarters, Jet Propulsion Laboratory, Armstrong Flight Research Center, Goddard Space Flight Center, and Langley Research Center—are working collaboratively to help target the UAVSAR instrument for daily radar imaging over the most critical rivers of interest to FEMA, the National Guard, and other partners. Scientists are assisting agencies in the interpretation of the UAVSAR imagery to inform immediate response efforts. They will also further process the data and use it as part of longer-term efforts to improve flood remote sensing and improve streamflow and inundation models.

Above: Civil Air Patrol photo taken on September 18, 2018 near Cheraw, SC. Credit: Civil Air Patrol

Above: UAVSAR polarimetric decomposition image taken on September 17, 2018 near Cheraw, SC (same area as Civil Air Patrol photo above). Pink denotes urban areas whereas red/orange denotes inundated forests. Dark blue or black are flooded open water; roads can be black even if not flooded. Green, yellow, and light blue color denote areas that are not flooded. Note: Red — Double bounce scattering (flooded forests and urban); Green – Volume scattering (unflooded forests); Blue – specular scatters (dry bare ground, open water). Credit: Yunling Lou/JPL, Bruce Chapman/JPL and Gerald Bawden/HQ

What NASA products are being shared with the National Guard and FEMA?

Most of our activities have focused on helping with the remote sensing of flooded areas following the heavy rains associated with Hurricane Florence. Many river basins in southern Virginia, central and eastern North Carolina, and northeastern South Carolina have experienced widespread river flooding and flash flooding that has affected citizens and need to be monitored for response efforts.

Above: This GPM IMERG visualization shows storm-total accumulated rainfall on the left for 9/12/18 – 9/17/18 vs. a sequence of 3-hour accumulations on the right. Credit: NASA

NASA Marshall team members are producing products and assisting with event coordination including my spot here at FEMA supporting their geospatial team. Scientists with the Jet Propulsion Laboratory (the ARIA team) are routinely generating flood- and damage proxy maps. Goddard researchers are assisting with optical and radar flood detections. The Langley Research Center is assisting with data access and sharing via GIS platforms. NASA Headquarters is supporting overall agency coordination. Johnson Space Center is helping to acquire dramatic footage of the storm and aftermath from astronaut photography.

What instruments are being used?

The extensive cloud cover from the storm has blocked surface views from instruments operating in the visible, near infrared, and thermal wavelengths, so synthetic aperture radar (SAR) information has been critical. SAR has the ability to “see” through clouds, making it an all-weather instrument. These include images from the European Space Agency’s Sentinel-1A/1B platforms, international and commercial partner assets, such as those from the Japan Aerospace Exploration Agency’s ALOS-2, Canadian Space Agency’s Radarsat-2, and the German TerraSARx, which are made available through government partnerships and the International Charter on Space and Major Disasters.

This flood proxy map shows the extent of flooding 36 hours after the hurricane’s landfall (September 15, 2018 18:57 PM local time). The map is derived from Synthetic Aperture Radar (SAR) data from the Copernicus Sentinel-1 satellites, operated by the European Space Agency (ESA).

As skies are now beginning to clear, we’ll also look for opportunities to use other NASA satellite remote sensing assets — including Terra/Aqua MODIS, Suomi-NPP VIIRS, Landsat 8 — and applications to identify water on the surface. We’ll also take a look at nighttime light imaging from Suomi-NPP VIIRS and the day-night band, using the NASA Black Marble and Black Marble HD products generated at Goddard.

Above: The VIIRS instrument on the joint NASA/NOAA Suomi NPP satellite observed Hurricane Florence as it developed in the Atlantic Ocean and made landfall in North Carolina on Sept. 14, 2018. Credits: NASA Worldview

 

Karenia brevis cells. Image credit: Mote Marine Laboratory

Put a sample of water from the Gulf of Mexico under a microscope, and you will often find cells of Karenia brevis swimming around. The microscopic algae—the species of phytoplankton responsible for Florida’s worst red tide outbreaks—produce brevetoxin, a compound that in high concentrations can kill wildlife and cause neurological, respiratory, and gastrointestinal issues for people.

Under normal conditions, water quality tests find, at most, a few hundred K. brevis cells per liter of water—not enough to cause problems. But in August 2018, in the midst of one of the most severe red tide outbreaks to hit Florida’s Gulf Coast in a decade, water samples regularly contained more than one million K. brevis cells per liter.

Natural-color MODIS satellite image of algae staining the water off the coast of Fort Myers on August 19, 2018. Image from the University of South Florida Near Real-Time Integrated Red tide Information System (IRIS).

That was enough to stain large swaths of coastal waters shades of green and brownish-red and leave beaches littered with rotting fish carcasses. Roughly 100 manatees, more than 200 sea turtles, and at least 12 dolphins have been killled by red tides, according to preliminary estimates. For much of August, the toxic bloom stretched about 130 miles (200 kilometers) along Florida’s Gulf coast, from roughly Tampa to Fort Myers. Though the bloom has been active since October 2017, it intensified rapidly in July 2018. The damage grew so severe and widespread that Florida’s governor declared a state of emergency in mid-August.

One of the best ways to test for the presence of K. brevis is to analyze water samples collected from boats or beaches. State environmental agencies do this on a regular basis, but understanding the full extent and evolution of fast-changing blooms, or predicting where they will move with ground sampling alone is a challenge.

Sampling red tide in 2018 (left). An aerial view of red tide in 2005 (right). Photo credits: Florida Fish and Wildlife Conservation Commission.

That’s why key red tide monitoring systems, such as the National Oceanic and Atmospheric Administration’s (NOAA’s) Harmful Algal Bloom Forecast System and the Near Real-Time Integrated Red Tide Information System (IRIS) from the University of South Florida, make use of satellite data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors on NASA’s Aqua and Terra satellites. These sensors pass over Florida’s Gulf Coast twice a day, acquiring data at several wavelengths that can be useful for identifying and mapping the spatial extent of algal blooms. Other satellite sensors such as the Visible Infrared Imaging Radiometer Suite (VIIRS) on Suomi NPP and the Ocean and Land Color Instrument (OCLI) on Sentinel-3 collect information that can be used to monitor red tides as well.

A screenshot from the University of South Florida’s Near Real-Time Integrated Red tide Information System (IRIS). The image shows various types of data captured by MODIS sensor on Terra on August 19, 2018. Solar-stimulated fluorescence data (NFLH) is particularly useful for locating algal blooms. Image Credit: USF/IRIS

Despite the utility of satellite observations, there are some significant challenges to interpreting satellite data of algal blooms in shallow, coastal waters, explained oceanographer Chuanmin Hu of the University of South Florida. Chief among them: it can be quite difficult to distinguish between algal blooms, suspended sediment, and colored dissolved organic matter (CDOM) that flows into coastal areas.

The Karenia brevis bloom expanded and intensified in late-July. This fluorescence data comes from the OCLI sensor on Sentinel 3. Image courtesy of Rick Stumpf, NOAA.

To get around this problem and make satellites better at pinpointing algal blooms, Hu and colleagues at the University of South Florida have developed a red tide monitoring system that makes use of MODIS observations of fluorescence, which algal bloom emit in response to exposure to sunlight. “If we have fluorescence data to go along with a natural-color image from MODIS, we can say with a high degree of confidence where the algal blooms are and where the sensor is just detecting sediment or CDOM,” he said. When fluorescence data is available, the Florida Fish and Wildlife Commission pushes it out to the public as part of its red tide status updates (see the August 21 update below).

Likewise, NOAA has combined a fluorescence method with a long-standing technique that identifies recent increases in chlorophyll concentration, the combination improves the identification of likely K. brevis blooms — information that then gets incorporated in NOAA’s HAB Forecast System, noted Richard Stumpf, an oceanographer with NOAA.

K. brevis cell abundance shown on an ocean color satellite image from the IRIS system. Warmer colors indicate higher levels of chlorophyll a, an indicator of algae. Cloudy areas are gray. Circles indicate locations where officials tested water samples on the ground. Image Credit: FFW/USF/IRIS.

However, that still leaves some big problems—only about ten percent of MODIS passes collect usable fluorescence data. The rest of the time images are marred by either sunglint or clouds. And the algorithm that scientists use to detect algal blooms with MODIS does not work well within one kilometer of the coast—the part that is of the greatest interest to beachgoers and boaters.

The Terra satellite. Image Credit: NASA

To help fill in the gaps, NASA’s Applied Science program is working with several partner institutions on a smartphone app called HABscope. The app, developed by Gulf of Mexico Observing System (GCOOS) researcher Robert Currier, makes it possible for trained water samplers (typically lifeguards who participate in Mote Marine Laboratory’s Beach Conditions Reporting System) to collect video of water using microscopes attached to their smartphones.

After recording, HABscope uploads videos to a cloud-based server for automatic analysis by computer software. The software rapidly counts the number of K. brevis cells in a water sample by using technology similar to that found in facial recognition apps. But rather than focusing on facial features, the software looks for a particular pattern in the movement of K. brevis cells.

K. brevis are vigorous swimmers, often using a pair of long, whip-like flagella to migrate vertically about 10 to 20 meters (33 to 66  feet) each day. They chart a zig-zagging, corkscrew-shaped path that allows the software to easily pick them out amidst the cast of other phytoplankton found in Gulf of Mexico water samples.

The data about K. brevis abundance at various locations along the coast is then fed into a respiratory distress forecasting tool managed by NOAA. “Respiratory distress forecasts can now be produced 1 to 2 times per day for specific beaches along the Florida Gulf Coast,” said Stumpf. “Previous to this project, these forecasts were issued at most twice a week, and only as general statements about risk within a county. The combination of earth observations with rapid field monitoring will increase the accuracy and usefulness of the forecasts.”

The research team that developed the HABscope app included oceanographers, ecologists, computer application developers, and public health experts. Photo Credit: Mote Marine Laboratory.

 

For more than two months, lava has been pouring from part of Hawaii’s Kilauea volcano, destroying homes and remaking the land surface. More data and imagery of the eruption is flowing in from satellites, drones, and ground-based sensors than Earth Observatory can cover, but here are a few striking images that we would be remiss not to share.

By The Lava’s Early Light
NASA Astronaut Ricky Arnold tweeted this nighttime photograph of lava on June 20, 2018. If the Star Spangled Banner had been composed in Hawaii rather than Baltimore, maybe “lava’s early light” would have made it into the lyrics. Credit: NASA


The Wrong Side of the Lava Flow


Notice the stark differences in landscapes on the northern and southern sides of the lava channel. With trade winds blowing heat and volcanic gases to the southwest, the north side remained green. Vegetation on the south side, yellowed and brown, took a battering. This aerial photograph was taken on July 10, 2018. Image Credit: USGS.


A Colorful Satellite Perspective on a Collapsing Caldera

As lava flows from some parts of Kilauea, other parts of the volcano have been sinking. In the case of the summit caldera, the rate of subsidence has been dramatic. This interferometric synthetic aperature radar (InSAR) image, or interferogram, shows surface movement at the summit caldera between June 9 and June 23. Each cycle of yellow-blue-purple indicates approximately 5 inches (13 centimeters) of movement. Areas where the colorful lines are the closest have shifted the most. The data was collected by Advanced Land Observing Satellite-2 (ALOS-2), a Japanese Aerospace Exploration Agency (JAXA) mission. Read more about this image and type of data from NASA’s Disasters Program. Image Credit: NASA/JAXA.

The Same Caldera Collapse Seen from the Ground


This sequence of images shows rapid subsidence of the caldera floor, along with the development of scarps. One photograph is shown per day between June 13 and 24. The photos were taken from the southern caldera rim, near Keanakāko‘i Crater, and face north. Image Credit: USGS.


Laze Billows into the Air as Lava Pours into the Sea


In this Sentinel-2 image,  a large plume of laze—steam, volcanic gases, and shards of glass—blows west over Hawaii as lava poured into the sea on June 27, 2018. Pierre Markuse created this image using data from Sentinel-2, a satellite managed by the European Space Agency. He regularly downloads and processes Sentinel and Landsat satellite data and has posted dozens of Kilauea images on Flickr. Image Credit: ESA/Sentinel-2/Markuse

Tracking the Kilauea Eruption

May 14th, 2018 by Adam Voiland

An active fissure in Leilani Estates subdivision. This photo shows fissure 7 on May 5, 2018. Image Credit: U.S. Geological Survey

You have probably seen dramatic images and videos of several new fissure eruptions cracking open the land surface in Hawaii, emitting plumes of gas, and spitting up fountains of lava in the middle of a residential neighborhood.

If you are tracking Kilauea’s eruptions, the U.S. Geological Survey Hawaiian Volcano Observatory (HVO) and Hawaii County Civil Defense are the best sources for the latest information. HVO releases status reports, photos, videos, maps, and near-real time data that are invaluable to understanding what is happening. Hawaii County issues frequent alerts with details about evacuations, road closures, and the status of utilities.

If you want to dig into the science of this eruption, HVO and the Smithsonian Global Volcanism Program both have informative summaries that synthesize what scientists know of Kilauea’s geologic history. There are also knowledgeable volcanologists tracking the eruption closely and offering science-based commentary. Janine Krippner of Concord University (@janinekrippner) is a trained volcanologist who tweets regularly about developments. Ken Rubin @kenhrubin), based at the University of Hawaii, does the same. Erik Klemetti, a volcanologist at Denison University, is reporting on the eruption on his Rocky Planet blog.

To extend the scientific conversation, Earth Matters reached out to a handful of researchers from NASA and elsewhere who are monitoring the volcano. Among those who responded were Simon Carn (Michigan Technological University), Ashley Davies (NASA Jet Propulsion Laboratory),  Jean-Paul Vernier (NASA Langley Research Center), Verity Flower (Universities Space Research Association/NASA Goddard Space Flight Center) and Krippner.

NASA astronaut Drew Feustel tweeted this photograph of a volcanic plume at the summit of Kilauea on May 13, 2018. Image Credit: NASA

Can you briefly describe the steps that happen in an eruption like we’re seeing with Kīlauea?
“First, USGS HVO tiltmeters recorded inflation of the volcano. This was caused by magma moving up from depth, causing the volcano to bulge outwards.  The lava lake level in the summit caldera (Halema’uma’u) rose, an indication of the influx of magma into the volcanic plumbing system. Local seismic activity increased due to rock breaking as magma forces its way upwards, and as the broader volcanic edifice adjusted and reacted to the changing stress field.  As magma rose, more volcanic gas (including sulfur dioxide) was released. As magma moved into the near surface East Rift Zone, the summit started to deflate, and the lava lake level dropped. There were structural adjustments along the rift, from the summit, to Pu’u O’o, and along the rift, causing earthquakes. Then lava erupted, the whole system began to depressurize, and deflation continued.”
– Ashley Davies

Starting on the afternoon of Monday, April 30, 2018, magma beneath Pu‘u ‘Ō‘ō drained and triggered the collapse of the crater floor. Within hours, earthquakes began migrating east of Pu‘u ‘Ō‘ō, signaling an intrusion of magma along the middle and lower East Rift Zone. Map credit: U.S. Geological Survey. More maps here.

How would you describe the significance or scope of this eruption?
“This eruption is part of the normal life cycle of Kilauea volcano and is comparable to past activity. In fact, 90 percent of the surface of Kilauea is less than 1,000 years old  very young on a geologic time scale. The significance of this eruption is that it is directly occurring in the Leilani community. These people need help and support. Even though we all live with natural hazards, no matter where we are, we don’t often imagine it happening to us.” Janine Krippner

What can we expect to happen next? Is the fissure eruption likely to persist for a long time?
“It could be a major risk to the Leilani Estates area if the eruption continues. So far, the lava flows have not traveled very far from the eruptive fissure. If this changes or the fissure extends in length, then more property will be destroyed and major roads could be cut.”
Simon Carn

This map overlays a georegistered mosaic of thermal images collected during a U.S. Geological Survey helicopter overflight of the fissures in Leilani Estates on May 9, 2018. The base is a copyrighted satellite image (used with permission) provided by Digital Globe. Temperature in the thermal image is displayed as gray-scale values, with the brightest pixels indicating the hottest areas (white shows active breakouts). Image: Courtesy of USGS, Copyright Digital Globe, NextView License.

“This eruption could persist for quite a while, but it is impossible to tell how long. This is a dynamic situation, and new fissures could start and stop with little to no warning. The risk of lava inundation is real and significant, depending on where lava is extruded at the surface and how much.” Janine Krippner

Can you address the health hazards associated with sulfur dioxide?
“The problem with sulfur dioxide is that if you breathe it in, it can combine with water in the lungs to create an acid. With sulfur dioxide issuing from the fissures in an inhabited area, it makes for unhealthy concentrations locally. HVO has more on this here.” Ashley Davies

This false-color ASTER image was acquired on May 6, 2018. It shows the sulfur dioxide plume in yellow and yellow-green coming from new activity in Leilani Estates. A smaller, but thicker, sulfur dioxide plume can be seen coming from Kilauea’s main vent. Image Credit: NASA/ASTER

“Sulfur dioxide is a common occurrence in Hawaii, as vog (volcanic smog), which is a mixture of sulfur and aerosols. Sulfur dioxide and/or vog can cause irritation to eyes and airways, causing coughing, wheezing, headaches, and sore throats. People with preexisting conditions, such as asthma, are more at risk. Sulfur dioxide levels have been measured at dangerous and deadly levels near the fissures.”  Janine Krippner

Volcanic gases rise from a fissure on Nohea Street, Leilani Estates. An HVO geologist measured a temperature of 103 degrees C (218 degree F). The asphalt road was describes as “mushy” from the heat. Image Credit: U.S. Geological Survey.

Which satellites sensors are making observations of Kilauea’s plume?
There are several. The Multi-angle Imaging SpectroRadiometer (MISR) can measure the height of plumes from stereo imagery, and makes observations of the size and shape of the particles, which is useful for determining the degree to which the plume is rich in liquid sulfate and water particles versus solid, angular ash particles. The Moderate Resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) are collecting daily snapshots of the amount of particulate matter in the plume as well as making observations of the sulfur dioxide plumes based on their thermal bands. The Operational Land Imager (OLI) and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) provide more detailed images, though overpasses are less frequent. Finally, synthetic aperture radar on Sentinel 1 is tracking how much the land deforms as the eruption progresses.
— Verity Flower

To what degree are satellites sensors like OMPS and OMI useful for monitoring sulfur dioxide emissions?
Satellites provide unique information on the total sulfur dioxide mass and spatial distribution in a plume ‘snapshot’, but provide minimal information on sulfur dioxide at ground level. Other techniques provide more localized measurements but can detect surface concentrations. Simon Carn

The Ozone Mapping Profiler Suite (OMPS) detected increasing concentrations of sulfur dioxide over Hawaii in May 2018. Image Credit: NASA Earth Observatory. Learn more about this map.

Are there other reasons to monitor volcanic plumes aside from health hazards?
The particles in volcanic ash have sharp, angular edges that can abrade aircraft windows hindering the pilots ability to navigate. Where these ash particles enter aircraft engines the high temperatures cause ash to melt, coating the rotors, air intakes and casings that can lead to engine failure. Plumes can also have effects—sometimes even positive effects—on the wider environment. Ash falls can destroy crops and damage infrastructure during an eruption, but they can also add nutrients to the ocean that fuel phytoplankton blooms and nutrients to the soil that make farmland more fertile on longer timescales. — Verity Flower

Can you tell me anything about the wind patterns around Hawaii?
So far, northwesterly trade winds, which are common in this area, have kept the plume over the ocean. The winds do occasionally shift for short periods, which could bring more volcanic pollution over populated areas. — Verity Flower

What has NASA been doing in response to the eruption?
“The NASA Disasters Program is working with several teams to assess the eruption and make information available to first responders and others. We are working with several instrument teams to monitor the sulfur dioxide plume. We are also looking at thermal imagery from VIIRS to detect the position of the new fissures. The VIIRS thermal anomaly is usually used for fire detection, but it appears to be a useful tool for detecting the fissure events in Leilani Estates. We are also using ASTER thermal anomaly data in near-real time to detect the fissures. You can find imagery and data from several sources showing different aspects of the eruption here.” Jean-Paul Vernier

A screenshot from a repository of maps and images related to the eruption compiled by the NASA Earth Science Disasters Program. Image Credit: NASA

 

Help NASA Create the Largest Landslide Database

April 18th, 2018 by Kasha Patel

This landslide occurred on June, 1, 2007 on a mountain near Canmore in Alberta, Canada. The Flickr photo was taken by Sheri Teris (Creative Commons)

Landslides cause thousands of deaths and billions of dollars in property damage each year. Surprisingly, very few centralized global landslide databases exist, especially those that are publicly available.

Now NASA scientists are working to fill the gap—and they want your help collecting information. In March 2018, NASA scientist Dalia Kirschbaum and several colleagues launched a citizen science project that will make it possible to report landslides you have witnessed, heard about in the news, or found on an online database. All you need to do is log into the Landslide Reporter portal and report the time, location, and date of the landslide—as well as your source of information. You are also encouraged to submit additional details, such as the size of the landslide and what triggered it. And if you have photos, you can upload them.

Kirschbaum’s team will review each entry and submit credible reports to the Cooperative Open Online Landslide Repository (COOLR) — which they hope will eventually be the largest global online landslide catalog available.

Landslide Reporter is designed to improve the quantity and quality of data in COOLR. Currently, COOLR contains NASA’s Global Landslide Catalog, which includes more than 11,000 reports on landslides, debris flows, and rock avalanches. Since the current catalog is based mainly on information from English language news reports and journalists tend to cover only large and deadly landslides in densely populated areas, many landslides never make it into the database. Landslide Reporter should help change this because it makes it possible for people to submit reports, including first-hand accounts, from anywhere in the world.

This map shows 2,085 landslides with fatalities as reported in the Global Landslide Catalog, which is currently included in the Cooperative Open Online Landslide Repository (COOLR). NASA Earth Observatory images by Joshua Stevens, using landslide susceptibility data provided by Thomas Stanley and Dalia Kirschbaum (NASA/GSFC).

Kirschbaum plans to use this database to improve the algorithm for her team’s landslide prediction model. The model, known as the Landslide Hazard Assessment for Situational Awareness (LHASA) model, analyzes rainfall and land characteristics in an area that might make a landslide more susceptible. The model produces forecasts of potential landslide activity every 30 minutes. In some cases, however, the model predicts more or less potential activity.

“With more ground data to validate the model, we can create a better tool for improving situational awareness and research for this pervasive hazard. We could better anticipate and forecast where landslides may impact populations,” said Kirschbaum.

Check out posts by Caroline Juang on Discover magazine’s citizen science blog and by David Petley on American Geophysical Union’s Landslide Blog to find out more. You can also follow the project on Twitter (@LandslideReport) and Facebook.

Why the SoCal Fires are So Fierce

December 7th, 2017 by Adam Voiland

NASA Earth Observatory image by Joshua Stevens, using MODIS data from LANCE/EOSDIS Rapid Response.

With thousands of homes threatened by intense wildfires burning in southern California, NASA Earth Observatory checked in with Jet Propulsion Laboratory scientist Natasha Stavros to learn more about the destructive blazes.

Earth Observatory (EO): Why have these fires been so fast-moving and destructive? Are fierce Santa Ana winds the key factor? Are anomalous temperatures, rainfall, ENSO conditions, bark beetle activity, or other factors playing an important role?

There are absolutely other factors. Santa Ana winds definitely played a role in spreading the fires, but the late fire season is a more complex story. Last year, we had a lot of heavy rains, and this increased fuel connectivity by enabling grasses and annual shrubs to flourish (hence the green hills last spring). However, we had a lot of record-breaking heat waves this year.

In fact, a recent study we conducted with NASA DEVELOP and the National Park Service in the Santa Monica Mountains showed that the number of days over 95 degrees Fahrenheit stressed established vegetation and contributed to massive die-off. Even though the drought is over, the trees are still recovering from the stress of reduced water availability for such an extended period. They are in a fragile state and their defenses are down. This means that they are even more susceptible to infestation, mortality, and ultimately fire danger.

EO: We have published MODIS (top of the page), Sentinel-2 (below), and nighttime VIIRS (bottom of the page) satellite imagery of these fires. Is there anything that you find particularly interesting or notable about these images?

To me, the noteworthy thing is that the plume is going over the ocean and not the continental United States (as we saw earlier this year). This has to do with the Santa Ana winds coming from the desert and pushing particulates, ozone, carbon monoxide, and other toxic pollutants away from where people live.

NASA Earth Observatory image by Joshua Stevens, using modified Copernicus Sentinel data (2017) processed by the European Space Agency.

As for the Sentinel-2 image, this is a great shot in that it really shows the value of remote sensing in monitoring fire. Flames that look like that are tens of meters tall. The flame length is proportional to the heat released from the flame, so these fires are very hot. Just like you would not want to stand too close to a bonfire with flames tens of meters tall, fire management does not want to put personnel in the path of those flames.

Images like these and fire behavior models help inform how we think the fire will move across the landscape. There is still a lot we do not know; our models are based on what we do know, so as fires become more intense, the models do not work as well, so this is an area of active research.

NASA Earth Observatory images by Joshua Stevens using VIIRS day-night band data from the Suomi National Polar-orbiting Partnership.

EO: Is there anything to say about how these fires fit into longer term trends and/or changing climate patterns?

Fire regimes are changing. There is no question about that, and there are a lot of things contributing to it: climate change, a century of fire exclusion, and a growing wildland urban interface (WUI). As we move into the future, we expect there to be an increase in very large fire events. Also, and this is relevant for the events happening now, there will be longer fire seasons. Also, note that many of the fires that ignite close to where people live are actually caused by people. This is particularly true in Southern California.

As we move forward, we need to think about how to support smart fire management practices. By that I mean: what can we proactively do to reduce fire risk (i.e. the threat to valuable resources)?

Most fires on the coasts are lit by people. NASA Earth Observatory map by Joshua Stevens, using fire data courtesy of Balch, J. et al. (2017).

EO: What about JPL’s response to these fires? I was intrigued by the megafire project described here. Will your group be responding to this fire in any way?

We just received approval from NASA Headquarters to fly the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) over these fires. This sensor has been useful for investigating fuel load type and subsequent effects on emission types, fire behavior, and post-fire analysis (e.g., safety, erosion, area burned, fire severity or the amount of environmental change caused the fire, etc.) and is often analyzed in interagency and federal-academic coordination to improve our understanding of fire.

Another effort to support fire management includes work being done from JPL in coordination with the National Interagency Fire Center (NIFC) to help them develop metrics of fire danger using NASA satellites that provide hydrologic variables (e.g., soil moisture and vapor pressure deficit—the difference between the amount of moisture in the air vs how much it can hold). These metrics have a one-month forecast to help allocate fire management resources nationally, which is particularly important as our fire seasons extend throughout the year in multiple places at the same time.

Natasha Stavros. Image courtesy of N. Stavros.

Taking Stock of a Smoky Fire Season

October 10th, 2017 by Adam Voiland

NASA Earth Observatory images by Jesse Allen, using VIIRS data from the Suomi National Polar-orbiting Partnership.

You have probably heard or read that it has been rather smoky out West this year. Dozens of large wildfires have raged through forests in British Columbia, Alberta, Washington, Oregon, Idaho, California, and other states this fire season. Intense blazes are lofting up so much smoke that huge plumes have been blowing across the country—and even turning up in Europe. We checked with a few scientists who specialize in studying wildfires for an update on what is going on.

EO: How does this fire season compare to past years?
The western fire season has been quite active this year. British Columbia has surpassed its greatest burned area in the modern era. While its unlikely that this season will be record-breaking in the western U.S., it is above normal relative to the past decade, which has seen abundant fire activity.
— John Abatzoglou, University of Idaho

EO: Is climate change exacerbating these fires?
Because we have let fuels build up in the western U.S., it is difficult to tell in many ecosystems what is weather-driven vs. climate-driven until we get back to normal fuel loads. This 2013 PNAS paper tries to answer the climate question given the artificially increased fuel loadings. They found that climate change is responsible for 55 percent of the observed increasing fuel aridity.  — Jessica McCarty, Miami University

EO: Are bark beetles making these fires worse?
No, the bark beetle outbreaks have little-to-no relationship with trends in area burned or the ecological severity of fires. I think this continues to be a big misconception with the public, which is understandable because climate is a key driver of both bark beetle outbreaks and wildfires. Many people jump to the conclusion that bark beetle outbreaks are causing fires. But it is likely a classic case of correlation without causation.  — Brian Harvey, University of Washington

EO: If there was one thing you wished Americans understood about wildfires in the West, what would it be?
Be careful with fire. Smokey the Bear is trying to educate you on the risk—listen. Heed fire risk and fire weather warnings. Don’t build campfires unless you have to. Don’t go off-roading during droughts and heat waves. Be careful with your cigarette butts.  — Jessica McCarty, Miami University

Even though no one is a fan of widespread smoke, wildfires aren’t inherently “bad” [when they are in unpopulated areas]. One continuing challenge is figuring out how to live with fire as part of the system as more people settle in the region during an era of changing environmental conditions. — John Abatzoglou, University of Idaho

NASA Earth Observatory images by Jesse Allen and Jeff Schmaltz, using Suomi NPP OMPS data provided courtesy of Colin Seftor (SSAI).

A June snowstorm just topped off the already thick layer of white stuff atop the Sierra Nevadas. California’s snow water equivalent rose to a heaping 170 percent of normal. But not so long ago, the state was in the midst of a deep drought; its mountains were bare and brown, and water levels plummeted in reservoirs.

Throughout, satellites were watching. Check out the California drought and its aftermath in a video from NASA Earth Observatory:

 

Image by the NASA GSFC Landsat/LDCM EPO Team using Landsat 5 data from the U.S. Geological Survey.

Twenty years ago this month, a hundred-year flood inundated cities along the Red River. The waters rose through April and May 1997, inundating 2,200 square miles (5,700 square kilometers) of North Dakota and Minnesotaa footprint twice as big as Rhode Island. The river spilled over its banks in Winnipeg, Canada, as well.

The false-color Landsat 5 image above shows Grand Forks, North Dakota, as it appeared on May 4, 1997. At that point, flood waters had mostly retreated, but the river still appeared swollen, with water lingering in floodplains just north of the city. Water appears dark blue, while structures are off-white.

There have been a several other notable floods since 1997. The river also overflowed its banks in 2006, 2009, and 2011.

In early May 2017, the river’s levels are average, and its water output holds steady, according to ground-based measurements taken at Grand Forks. Yet, the country as a whole just experienced its second-wettest April on record, with severe floods along the Mississippi River.

The U.S. Geological Survey has additional satellite imagery and a gallery of ground photographs of the flood. The Star Tribune has a good story that looks at how Grand Forks has fared since 1997.

Blizzard 2017: Not In Denver, but in Hawaii

March 10th, 2017 by Pola Lem

In Hawaii, land of palm trees, pineapples, and year-round surfing, a full-blown blizzard hit last week. The early March storm brought more than 8 inches (20 centimeters) to the top of Mauna Kea volcano, leading authorities to shut the road to the peak.

The snow was all the more surprising given how little has fallen in more traditionally snowy locales. Hawaii received more snow that day than Denver has accumulated over the past seven weeks. The Colorado city got 1.6 inches (4 centimeters) in the past 51 days, according to local news.

The island archipelago also got more white stuff than Chicago. That city, famed for its bitter winters, is currently in the midst of a snow drought, with a mere 0.6 inches (1.5 centimeters) falling in 2017. That’s the least on record since the late 1800s. To put that into perspective: Chicago averages 37 inches (94 cm) of yearly snowfall. By contrast, Hawaii gets a yearly average of 3.7 inches (9 cm).

Thanks to their height, the peaks of Mauna Kea and Mauna Loa volcanoes do receive a dusting now and again. But that snow rarely sticks around for more than a few days, according to Ken Rubin, an assistant professor of geology and geophysics at the University of Hawaii.

Mauna Kea in December 2016. Image: NASA Earth Observatory/Jesse Allen, using Landsat data from the U.S. Geological Survey.