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Pacific Moisture Drenches the U.S. Northwest
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Waves of heavy rainfall in early December 2025 spurred landslides and flooding in parts of the Pacific Northwest. The deluge was the result of a potent atmospheric river that took aim at the region starting around December 7.
Atmospheric rivers are long, narrow bands of moisture that move like rivers in the sky, transporting water vapor from the tropics toward the poles. They occur around the planet, most often in autumn and winter, with the U.S. West Coast typically affected by moist air that originates near Hawaii. In this event, however, some of the moisture arrived from even farther away, originating roughly 7,000 miles (11,000 kilometers) across the Pacific from near the Philippines.
This map shows the total precipitable water vapor in the atmosphere at 11:30 p.m. Pacific Time on December 10. It is derived from NASA’s GEOS (Goddard Earth Observing System) and uses satellite data and models of physical processes to approximate what is happening in the atmosphere.
Precipitable water vapor represents the amount of water contained in a column of air, assuming all the water vapor condensed into liquid. The map’s green areas indicate the highest amounts of moisture. Note that not all precipitable water vapor falls as rain; at least some remains in the atmosphere. Nor is it a cap on how much rain can fall, since rainfall can increase as more moisture flows into a column of air. Still, it serves as a useful indicator of areas where excessive rainfall is likely.
According to the National Weather Service, preliminary ground-based measurements showed that several locations in western Washington received more than 10 inches (250 millimeters) of rain over a 72-hour period ending on the morning of December 11. Seattle-Tacoma International Airport set a daily rainfall record on December 10, with 1.6 inches (40 millimeters).
River flooding was ongoing on December 11, with the Skagit River and Snohomish River seeing record or near-record flood levels that day. Floodwater and mudslides have closed numerous roadways, including the eastbound lanes of I-90 out of western Washington.
NASA’s Disasters Response Coordination System has been activated to support the ongoing response efforts by the Washington State Emergency Operations Center. The team will be posting maps and data products on its open-access mapping portal as new information becomes available.
NASA Earth Observatory images by Lauren Dauphin, using GEOS data from the Global Modeling and Assimilation Office at NASA GSFC. Story by Kathryn Hansen.
References & Resources- Cliff Mass Weather Blog (2025, December 8) The Torrent Has Begun: The Philippine Connection. Accessed December 11, 2025.
- National Water Center, via X (2025, December 10) Key Messages for Pacific Northwest Flooding. Accessed December 11, 2025.
- National Weather Service (2025, December 11) Miscellaneous Hydrological Data. Accessed December 11, 2025.
- NOAA (2025, February 21) What are atmospheric rivers? Accessed December 11, 2025.
- USA Today (2025, December 11) Catastrophic flooding sparks evacuations in Washington state. See forecast. Accessed December 11, 2025.
- The Washington Post (2025, December 8) A 7,000-mile atmospheric river is stretching from Philippines to the U.S. Accessed December 11, 2025.
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To learn more about NASA heliophysics missions, visit:
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Abbey Interrante / Karen Fox
Headquarters, Washington
301-201-0124 / 202-358-1600
abbey.a.interrante@nasa.gov / karen.c.fox@nasa.gov
NASA Selects Two Heliophysics Missions for Continued Development
NASA has selected one small explorer mission concept to advance toward flight design and another for an extended period of concept development.
NASA’s Science Mission Directorate Science Management Council selected CINEMA (Cross-scale Investigation of Earth’s Magnetotail and Aurora) to enter Phase B of development, which includes planning and design for flight and mission operations. The principal investigator for the CINEMA mission concept is Robyn Millan from Dartmouth College in Hanover, New Hampshire.
The proposed CINEMA mission aims to advance our understanding of how plasma energy flows into the Earth’s magnetosphere. This highly dynamic convective flow is unpredictable — sometimes steady and sometimes explosive — driving phenomena like fast plasma jets, global electrical current systems, and spectacular auroral displays.
“The CINEMA mission will help us to research magnetic convection in Earth’s magnetosphere — a critical piece of the puzzle in understanding why some space weather events are so influential, such as causing magnificent aurora displays and impacts to ground- and space-based infrastructure, and others seem to fizzle out,” said Joe Westlake, director of the Heliophysics Division at NASA Headquarters in Washington. “Using multiple, multi-point measurements to improve predictions of these impacts on humans and technology across the solar system is a key strategy for the future of heliophysics research.”
The CINEMA mission’s constellation of nine small satellites will investigate the convective mystery using a combination of instruments — an energetic particle detector, an auroral imager, and a magnetometer — on each spacecraft in a polar low Earth orbit. By relating the energetic particles observed in this orbit to simultaneous auroral images and local magnetic field measurements, CINEMA aims to connect energetic activity in Earth’s large-scale magnetic structure to the visible signatures like aurora that we see in the ionosphere. The mission has been awarded approximately $28 million to enter Phase B. The total cost of the mission, not including launch, will not exceed $182.8 million. Phase B will last 10 months, and if selected, the mission would launch no earlier than 2030.
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The CMEx concept is a proposed single-spacecraft mission that would use proven UV spectropolarimetric instrumentation that has been demonstrated during NASA’s CLASP (Chromospheric Layer Spectropolarimeter) sub-orbital sounding rocket flight. Using this heritage hardware, CMEx would be able to diagnose lower layers of the Sun’s chromosphere to understand the origin of solar eruptions and determine the magnetic sources of the solar wind.
The proposed missions completed a one-year early concept study in response to the 2022 Heliophysics Explorers Program Small-class Explorer (SMEX) Announcement of Opportunity.
“Space is becoming increasingly more important and plays a role in just about everything we do,” said Asal Naseri, acting associate flight director for heliophysics at NASA Headquarters. “These mission concepts, if advanced to flight, will improve our ability to predict solar events that could harm satellites that we rely on every day and mitigate danger to astronauts near Earth, at the Moon, or Mars.”
To learn more about NASA heliophysics missions, visit:
https://science.nasa.gov/heliophysics
-end-
Abbey Interrante / Karen Fox
Headquarters, Washington
301-201-0124 / 202-358-1600
abbey.a.interrante@nasa.gov / karen.c.fox@nasa.gov
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Preparations for Next Moonwalk Simulations Underway (and Underwater) The 2025 Boeing ecoDemonstrator Explorer, a United Airlines 737-8, sits outside a United hangar in Houston.Boeing / Paul Weatherman
Picture this: You’re just about done with a transoceanic flight, and the tracker in your seat-back screen shows you approaching your destination airport. And then … you notice your plane is moving away. Pretty far away. You approach again and again, only to realize you’re on a long, circling loop that can last an hour or more before you land.
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This inconvenience to travelers is also an economic and efficiency challenge for the aviation sector, which is why NASA has worked for years to study the issue, and recently teamed with Boeing to conduct real-time tests an advanced system that shares trajectory data between an aircraft and its support systems.
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This partnership has allowed NASA to further its commitment to transformational aviation research.Shivanjli sharma
NASA's Air Traffic Management—eXploration project manager
The testing was Boeing’s most recent ecoDemonstrator Explorer program, through which the company works with public and private partners to accelerate aviation innovations. This year’s ecoDemonstrator flight partners included NASA, the Federal Aviation Administration, United Airlines, and several aerospace companies as well as academic and government researchers.
NASA’s work in the testing involved the development of an oceanic trajectory prediction service – a system for sharing and updating trajectory information, even over a long, transoceanic flight that involves crossing over from U.S. air traffic systems into those of another country. The collaboration allowed NASA to get a more accurate look at what’s required to reduce gaps in data sharing.
“At what rate do you need these updates in an oceanic environment?” Sharma said. “What information do you need from the aircraft? Having the most accurate trajectory information will allow aircraft to move more efficiently around the globe.”
Boeing and the ecoDemonstrator collaborators plan to use the flight data to move the data communication system toward operational service. The work has allowed NASA to continue its work to improve trajectory prediction, and through its connection with partners, put its research into practical use as quickly as possible.
“This partnership has allowed NASA to further its commitment to transformational aviation research,” Sharma said. “Bringing our expertise in trajectory prediction together with the contributions of so many innovative partners contributes to global aviation efficiency that will yield real benefits for travelers and industry.”
NASA ATM-X’s part in the collaboration falls under the agency’s Airspace Operations and Safety Program, which works to enable safe, efficient aviation transportation operations that benefit the flying public and industry. The work is supported through NASA’s Aeronautics Research Mission Directorate.
Facebook logo @NASA@NASAaero@NASAes @NASA@NASAaero@NASA_es Instagram logo @NASA@NASAaero@NASA_es Linkedin logo @NASA Explore More 2 min read NASA Demonstrates Safer Skies for Future Urban Air Travel Article 3 days ago 5 min read New NASA Sensor Goes Hunting for Critical Minerals Article 4 days ago 4 min read NASA Software Raises Bar for Aircraft Icing Research Article 1 week ago Keep Exploring Discover More Topics From NASAMissions
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Preparations for Next Moonwalk Simulations Underway (and Underwater) The 2025 Boeing ecoDemonstrator Explorer, a United Airlines 737-8, sits outside a United hangar in Houston.Boeing / Paul WeathermanPicture this: You’re just about done with a transoceanic flight, and the tracker in your seat-back screen shows you approaching your destination airport. And then … you notice your plane is moving away. Pretty far away. You approach again and again, only to realize you’re on a long, circling loop that can last an hour or more before you land.
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“Often, if there’s a change in your trajectory – you’re arriving slightly early, you’re arriving slightly late – you can get stuck in this really long, rotational holding pattern,” said Shivanjli Sharma, NASA’s Air Traffic Management–eXploration (ATM-X) project manager and the agency’s Ames Research Center in California’s Silicon Valley.
This inconvenience to travelers is also an economic and efficiency challenge for the aviation sector, which is why NASA has worked for years to study the issue, and recently teamed with Boeing to conduct real-time tests an advanced system that shares trajectory data between an aircraft and its support systems.
Boeing began flying a United Airlines 737 for about two weeks in October testing a data communication system designed to improve information flow between the flight deck, air traffic control, and airline operation centers. The work involved several domestic flights based in Houston, as well as flight over the Atlantic to Edinburgh, Scotland.
This partnership has allowed NASA to further its commitment to transformational aviation research.Shivanjli sharma
NASA's Air Traffic Management—eXploration project manager
The testing was Boeing’s most recent ecoDemonstrator Explorer program, through which the company works with public and private partners to accelerate aviation innovations. This year’s ecoDemonstrator flight partners included NASA, the Federal Aviation Administration, United Airlines, and several aerospace companies as well as academic and government researchers.
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“At what rate do you need these updates in an oceanic environment?” Sharma said. “What information do you need from the aircraft? Having the most accurate trajectory information will allow aircraft to move more efficiently around the globe.”
Boeing and the ecoDemonstrator collaborators plan to use the flight data to move the data communication system toward operational service. The work has allowed NASA to continue its work to improve trajectory prediction, and through its connection with partners, put its research into practical use as quickly as possible.
“This partnership has allowed NASA to further its commitment to transformational aviation research,” Sharma said. “Bringing our expertise in trajectory prediction together with the contributions of so many innovative partners contributes to global aviation efficiency that will yield real benefits for travelers and industry.”
NASA ATM-X’s part in the collaboration falls under the agency’s Airspace Operations and Safety Program, which works to enable safe, efficient aviation transportation operations that benefit the flying public and industry. The work is supported through NASA’s Aeronautics Research Mission Directorate.
Facebook logo @NASA@NASAaero@NASAes @NASA@NASAaero@NASA_es Instagram logo @NASA@NASAaero@NASA_es Linkedin logo @NASA Explore More 2 min read NASA Demonstrates Safer Skies for Future Urban Air Travel Article 5 days ago 5 min read New NASA Sensor Goes Hunting for Critical Minerals Article 5 days ago 4 min read NASA Software Raises Bar for Aircraft Icing Research Article 1 week ago Keep Exploring Discover More Topics From NASAMissions
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A team of astronomers used data from over 1,600 galaxies collected in more than two decades of the Chandra mission. The researchers looked at galaxies ranging in heft from over ten times the mass of the Milky Way down to dwarf galaxies, which have stellar masses less than a few percent of that of our home galaxy. A paper describing these results has been published in The Astrophysical Journal and is available here https://arxiv.org/abs/2510.05252.
The team has reported that only about 30% of dwarf galaxies likely contain supermassive black holes.
“It’s important to get an accurate black hole head count in these smaller galaxies,” said Fan Zou of the University of Michigan in Ann Arbor, who led the study. “It’s more than just bookkeeping. Our study gives clues about how supermassive black holes are born. It also provides crucial hints about how often black hole signatures in dwarf galaxies can be found with new or future telescopes.”
As material falls onto black holes, it is heated by friction and produces X-rays. Many of the massive galaxies in the study contain bright X-ray sources in their centers, a clear signature of supermassive black holes in their centers. The team concluded that more than 90% of massive galaxies – including those with the mass of the Milky Way – contain supermassive black holes.
However, smaller galaxies in the study usually did not have these unambiguous black hole signals. Galaxies with masses less than three billion Suns – about the mass of the Large Magellanic Cloud, a close neighbor to the Milky Way – usually do not contain bright X-ray sources in their centers.
The researchers considered two possible explanations for this lack of X-ray sources. The first is that the fraction of galaxies containing massive black holes is much lower for these less massive galaxies. The second is the amount of X-rays produced by matter falling onto these black holes is so faint that Chandra cannot detect it.
“We think, based on our analysis of the Chandra data, that there really are fewer black holes in these smaller galaxies than in their larger counterparts,” said Elena Gallo, a co-author also from the University of Michigan.
To reach their conclusion, Zou and his colleagues considered both possibilities for the lack of X-ray sources in small galaxies in their large Chandra sample. The amount of gas falling onto a black hole determines how bright or faint they are in X-rays. Because smaller black holes are expected to pull in less gas than larger black holes, they should be fainter in X-rays and often not detectable. The researchers confirmed this expectation.
However, they found that an additional deficit of X-ray sources is seen in less massive galaxies beyond the expected decline from decreases in the amount of gas falling inwards. This additional deficit can be accounted for if many of the low-mass galaxies simply don’t have any black holes at their centers. The team’s conclusion was that the drop in X-ray detections in lower mass galaxies reflects a true decrease in the number of black holes located in these galaxies.
This result could have important implications for understanding how supermassive black holes form. There are two main ideas: In the first, a giant gas cloud directly collapses into a black hole, which contains thousands of times the Sun’s mass from the start. The other idea is that supermassive black holes instead come from much smaller black holes, created when massive stars collapse.
“The formation of big black holes is expected to be rarer, in the sense that it occurs preferentially in the most massive galaxies being formed, so that would explain why we don’t find black holes in all the smaller galaxies,” said co-author Anil Seth of the University of Utah.
This study supports the theory where giant black holes are born already weighing several thousand times the Sun’s mass. If the other idea were true, the researchers said they would have expected smaller galaxies to likely have the same fraction of black holes as larger ones.
This result also could have important implications for the rates of black hole mergers from the collisions of dwarf galaxies. A much lower number of black holes would result in fewer sources of gravitational waves to be detected in the future by the Laser Interferometer Space Antenna. The number of black holes tearing stars apart in dwarf galaxies will also be smaller.
NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.
To learn more about Chandra, visit:
https://science.nasa.gov/chandra
Read more from NASA’s Chandra X-ray Observatory
Learn more about the Chandra X-ray Observatory and its mission here:
News Media ContactMegan Watzke
Chandra X-ray Center
Cambridge, Mass.
617-496-7998
mwatzke@cfa.harvard.edu
Corinne Beckinger
Marshall Space Flight Center, Huntsville, Alabama
256-544-0034
corinne.m.beckinger@nasa.gov
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NASA’s Chandra Finds Small Galaxies May Buck the Black Hole Trend
Most smaller galaxies may not have supermassive black holes in their centers, according to a recent study using NASA’s Chandra X-ray Observatory. This contrasts with the common idea that nearly every galaxy has one of these giant black holes within their cores, as NASA leads the world in exploring how our universe works.
A team of astronomers used data from over 1,600 galaxies collected in more than two decades of the Chandra mission. The researchers looked at galaxies ranging in heft from over ten times the mass of the Milky Way down to dwarf galaxies, which have stellar masses less than a few percent of that of our home galaxy. A paper describing these results has been published in The Astrophysical Journal and is available here https://arxiv.org/abs/2510.05252.
The team has reported that only about 30% of dwarf galaxies likely contain supermassive black holes.
“It’s important to get an accurate black hole head count in these smaller galaxies,” said Fan Zou of the University of Michigan in Ann Arbor, who led the study. “It’s more than just bookkeeping. Our study gives clues about how supermassive black holes are born. It also provides crucial hints about how often black hole signatures in dwarf galaxies can be found with new or future telescopes.”
As material falls onto black holes, it is heated by friction and produces X-rays. Many of the massive galaxies in the study contain bright X-ray sources in their centers, a clear signature of supermassive black holes in their centers. The team concluded that more than 90% of massive galaxies – including those with the mass of the Milky Way – contain supermassive black holes.
However, smaller galaxies in the study usually did not have these unambiguous black hole signals. Galaxies with masses less than three billion Suns – about the mass of the Large Magellanic Cloud, a close neighbor to the Milky Way – usually do not contain bright X-ray sources in their centers.
The researchers considered two possible explanations for this lack of X-ray sources. The first is that the fraction of galaxies containing massive black holes is much lower for these less massive galaxies. The second is the amount of X-rays produced by matter falling onto these black holes is so faint that Chandra cannot detect it.
“We think, based on our analysis of the Chandra data, that there really are fewer black holes in these smaller galaxies than in their larger counterparts,” said Elena Gallo, a co-author also from the University of Michigan.
To reach their conclusion, Zou and his colleagues considered both possibilities for the lack of X-ray sources in small galaxies in their large Chandra sample. The amount of gas falling onto a black hole determines how bright or faint they are in X-rays. Because smaller black holes are expected to pull in less gas than larger black holes, they should be fainter in X-rays and often not detectable. The researchers confirmed this expectation.
However, they found that an additional deficit of X-ray sources is seen in less massive galaxies beyond the expected decline from decreases in the amount of gas falling inwards. This additional deficit can be accounted for if many of the low-mass galaxies simply don’t have any black holes at their centers. The team’s conclusion was that the drop in X-ray detections in lower mass galaxies reflects a true decrease in the number of black holes located in these galaxies.
This result could have important implications for understanding how supermassive black holes form. There are two main ideas: In the first, a giant gas cloud directly collapses into a black hole, which contains thousands of times the Sun’s mass from the start. The other idea is that supermassive black holes instead come from much smaller black holes, created when massive stars collapse.
“The formation of big black holes is expected to be rarer, in the sense that it occurs preferentially in the most massive galaxies being formed, so that would explain why we don’t find black holes in all the smaller galaxies,” said co-author Anil Seth of the University of Utah.
This study supports the theory where giant black holes are born already weighing several thousand times the Sun’s mass. If the other idea were true, the researchers said they would have expected smaller galaxies to likely have the same fraction of black holes as larger ones.
This result also could have important implications for the rates of black hole mergers from the collisions of dwarf galaxies. A much lower number of black holes would result in fewer sources of gravitational waves to be detected in the future by the Laser Interferometer Space Antenna. The number of black holes tearing stars apart in dwarf galaxies will also be smaller.
NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.
To learn more about Chandra, visit:
https://science.nasa.gov/chandra
Read more from NASA’s Chandra X-ray Observatory
Learn more about the Chandra X-ray Observatory and its mission here:
News Media ContactMegan Watzke
Chandra X-ray Center
Cambridge, Mass.
617-496-7998
mwatzke@cfa.harvard.edu
Corinne Beckinger
Marshall Space Flight Center, Huntsville, Alabama
256-544-0034
corinne.m.beckinger@nasa.gov
A new sonification turns X-ray data of “light echoes” captured by NASA’s Chandra and Swift…
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