John Hammond
@hydrohammond.bsky.social
Research hydrologist and river photographer. www.riversfromabove.com
Pinned
John Hammond
@hydrohammond.bsky.social
· Mar 20
Hydrological Whiplash: Highlighting the Need for Better Understanding and Quantification of Sub‐Seasonal Hydrological Extreme Transitions
Hydrological whiplash, or the sub-seasonal transition between hydrological extremes, has broad implications for water resource management, ecosystems, infrastructure, and human society. As this pheno...
doi.org
Science! Super proud of this commentary that results from conversations started at @agu.org in December. We propose the term hydrological whiplash, sub-seasonal transitions between hydrological extremes, and outline why we think this topic needs greater attention.
doi.org/10.1002/hyp....
doi.org/10.1002/hyp....
New preprint led by Aaron Heldmyer and Roy Sando: Random forest + donor gages to predict daily streamflow drought across CONUS. Regional drivers differ—soil moisture, precip, SWE matter most. doi.org/10.5194/egus...
January 21, 2026 at 4:42 PM
New preprint led by Aaron Heldmyer and Roy Sando: Random forest + donor gages to predict daily streamflow drought across CONUS. Regional drivers differ—soil moisture, precip, SWE matter most. doi.org/10.5194/egus...
🔥💧 New paper out in Environmental Research: Water led by Brian Ebel!
Synthesis shows how wildfires fundamentally shift hydrologic processes and streamflow generation—from infiltration and runoff to baseflow and flood response — post wildfire.
iopscience.iop.org/article/10.1...
Synthesis shows how wildfires fundamentally shift hydrologic processes and streamflow generation—from infiltration and runoff to baseflow and flood response — post wildfire.
iopscience.iop.org/article/10.1...
A review and synthesis of post-wildfire shifts in hydrologic processes and streamflow generation mechanisms
A review and synthesis of post-wildfire shifts in hydrologic processes and streamflow generation mechanisms, Ebel, Brian A, Hammond, John C, Walvoord, Michelle A, Partridge, Trevor F, Rey, David M, Murphy, Sheila F
iopscience.iop.org
January 15, 2026 at 9:51 PM
🔥💧 New paper out in Environmental Research: Water led by Brian Ebel!
Synthesis shows how wildfires fundamentally shift hydrologic processes and streamflow generation—from infiltration and runoff to baseflow and flood response — post wildfire.
iopscience.iop.org/article/10.1...
Synthesis shows how wildfires fundamentally shift hydrologic processes and streamflow generation—from infiltration and runoff to baseflow and flood response — post wildfire.
iopscience.iop.org/article/10.1...
Reposted by John Hammond
If you know an undergraduate looking for a geosciences REU program, our applications are due in one month! Focus this year on community, air, and water projects!
sites.google.com/view/csaw-re...
sites.google.com/view/csaw-re...
CSAW REU
Overview
sites.google.com
January 12, 2026 at 5:59 PM
If you know an undergraduate looking for a geosciences REU program, our applications are due in one month! Focus this year on community, air, and water projects!
sites.google.com/view/csaw-re...
sites.google.com/view/csaw-re...
Reposted by John Hammond
I wrote a commentary discussing Daniele's huge new global synthesis of controls on hydrological processes in forested catchments: read it here: rdcu.be/eXTrq . Some surprising findings on the importance of overland flow, soils and antecedent conditions.
January 7, 2026 at 4:54 PM
I wrote a commentary discussing Daniele's huge new global synthesis of controls on hydrological processes in forested catchments: read it here: rdcu.be/eXTrq . Some surprising findings on the importance of overland flow, soils and antecedent conditions.
Reposted by John Hammond
New paper! Real-time flood inundation mapping (FIM) services are an incredibly valuable tool for emergency management and affected communities. But do their visualizations help users quickly and accurately interpret information to make decisions? onlinelibrary.wiley.com/doi/10.1002/...
Comparing Flood Inundation Map Features and Diagnosing Decision Support Design Challenges
Using visualisation typologies, we developed a diagnostic evaluation method for eight user-controlled ensemble FIM visualisations. Key design challenges include unclear messaging, non-accessible and ...
onlinelibrary.wiley.com
January 7, 2026 at 9:27 PM
New paper! Real-time flood inundation mapping (FIM) services are an incredibly valuable tool for emergency management and affected communities. But do their visualizations help users quickly and accurately interpret information to make decisions? onlinelibrary.wiley.com/doi/10.1002/...
Reposted by John Hammond
How do #climate, #antecedent #moisture, #soils, #topography, #geology, and #vegetation control #runoff #processes in #forested #catchments worldwide? Find this out here rdcu.be/eXTtd! @natwater.nature.com
Thanks a lot @mcmillanhydro.bsky.social for this commentary
www.nature.com/articles/s44...!
Thanks a lot @mcmillanhydro.bsky.social for this commentary
www.nature.com/articles/s44...!
January 7, 2026 at 9:15 AM
How do #climate, #antecedent #moisture, #soils, #topography, #geology, and #vegetation control #runoff #processes in #forested #catchments worldwide? Find this out here rdcu.be/eXTtd! @natwater.nature.com
Thanks a lot @mcmillanhydro.bsky.social for this commentary
www.nature.com/articles/s44...!
Thanks a lot @mcmillanhydro.bsky.social for this commentary
www.nature.com/articles/s44...!
I’ve always been more of a photographer than anything else when it comes to art. Still trying sketching sometimes, but also enjoying creating vector art versions of my #riversfromabove photos, and some other travel photos. I feel like style is “you love/hate it” without much in the middle. Thoughts?
January 1, 2026 at 12:17 AM
I’ve always been more of a photographer than anything else when it comes to art. Still trying sketching sometimes, but also enjoying creating vector art versions of my #riversfromabove photos, and some other travel photos. I feel like style is “you love/hate it” without much in the middle. Thoughts?
Reposted by John Hammond
A piece that felt particularly relevant to write
‼️ Hot off the press in @natwater.nature.com: "Riverine heatwaves are an emergent climate change risk"
We
🐟 (1) highlight the impacts of and unknowns related to riverine heatwaves and
🤔 (2) discuss the research needed to improve our knowledge.
Link to article: www.nature.com/articles/s44...
We
🐟 (1) highlight the impacts of and unknowns related to riverine heatwaves and
🤔 (2) discuss the research needed to improve our knowledge.
Link to article: www.nature.com/articles/s44...
Riverine heatwaves are an emergent climate change risk - Nature Water
Riverine heatwaves have severe consequences for society, the economy and ecosystems and are becoming more frequent with climate change. This Perspective addresses research efforts to better understand...
www.nature.com
December 3, 2025 at 12:27 PM
A piece that felt particularly relevant to write
Reposted by John Hammond
Check out the end-of-the-year blogpost about model design by Jonathan Frame!
deepgroundwater.com/blog/what-do...
deepgroundwater.com/blog/what-do...
What does your model do? - Deep Groundwater
A collection of open-source blog posts and articles
deepgroundwater.com
December 29, 2025 at 6:42 PM
Check out the end-of-the-year blogpost about model design by Jonathan Frame!
deepgroundwater.com/blog/what-do...
deepgroundwater.com/blog/what-do...
Reposted by John Hammond
New paper in WRR: Snow Sublimation Significantly Decreases Following Stand-Replacing Fire With Minor Water Balance Impacts From Forest Thinning in a Water Limited Forest. find it here: doi.org/10.1029/2025...
Snow Sublimation Significantly Decreases Following Stand‐Replacing Fire With Minor Water Balance Impacts From Forest Thinning in a Water Limited Forest
Snow sublimation is significantly reduced following a wildfire A thinning prescription that targeted ladder fuels and white fir had minimal impacts on sublimation and the overall water balance
doi.org
December 29, 2025 at 4:26 PM
New paper in WRR: Snow Sublimation Significantly Decreases Following Stand-Replacing Fire With Minor Water Balance Impacts From Forest Thinning in a Water Limited Forest. find it here: doi.org/10.1029/2025...
Reposted by John Hammond
Hydrology Paper of the Day @andy-baker.bsky.social on quantifying the drip of water underground as part of rainfall recharge: groundwater monitoring near the water table in Australia; why mines, tunnels and caves are essential monitoring locations; and relating rock aquifer response to rainfall.
We have a new position paper, where we advocate for the wider use of underground observatories to understand how groundwater is replenished.
By directly observing these recharge events, we can make a direct link between groundwater replenishment, weather and climate.
eos.org/science-upda...
By directly observing these recharge events, we can make a direct link between groundwater replenishment, weather and climate.
eos.org/science-upda...
When Does Rainfall Become Recharge? - Eos
Counting drips in caves is helping to reveal how much precipitation is needed to start refilling underground aquifers.
eos.org
December 27, 2025 at 1:56 AM
Hydrology Paper of the Day @andy-baker.bsky.social on quantifying the drip of water underground as part of rainfall recharge: groundwater monitoring near the water table in Australia; why mines, tunnels and caves are essential monitoring locations; and relating rock aquifer response to rainfall.
Reposted by John Hammond
Working with large-sample hydrology datasets and curious about how maps with varying levels of detail influence the identification of geology–streamflow relationships? Check out our latest preprint at HESS!
#Hydrology #CatchmentHydrology #LargeSampleHydrology #Eawag #hightlightpaper #HESS
#Hydrology #CatchmentHydrology #LargeSampleHydrology #Eawag #hightlightpaper #HESS
How do geological map details influence the identification of geology-streamflow relationships in large-sample hydrology studies?
Abstract. Large-sample hydrology datasets have advanced hydrological research, yet the impact of landscape map details on identifying dominant streamflow generation processes remains underexplored. Th...
doi.org
December 19, 2025 at 10:36 PM
Working with large-sample hydrology datasets and curious about how maps with varying levels of detail influence the identification of geology–streamflow relationships? Check out our latest preprint at HESS!
#Hydrology #CatchmentHydrology #LargeSampleHydrology #Eawag #hightlightpaper #HESS
#Hydrology #CatchmentHydrology #LargeSampleHydrology #Eawag #hightlightpaper #HESS
@rarakihydro.bsky.social leads an exiting new preprint that maps dominant hydrologic processes across >14k US watersheds using streamflow signatures + ML. It’s been such fun following Ryoko and Hilary’s leadership alongside Admin, Anne and Gemma.
egusphere.copernicus.org/preprints/20...
egusphere.copernicus.org/preprints/20...
December 18, 2025 at 6:32 PM
@rarakihydro.bsky.social leads an exiting new preprint that maps dominant hydrologic processes across >14k US watersheds using streamflow signatures + ML. It’s been such fun following Ryoko and Hilary’s leadership alongside Admin, Anne and Gemma.
egusphere.copernicus.org/preprints/20...
egusphere.copernicus.org/preprints/20...
Reposted by John Hammond
Excited to unveil Caravan-Qual! 🌊
We've expanded the Caravan framework to bridge the gap between water quantity and quality.
This new open dataset features: 🔹 ~70M observations 🔹137k stations 🔹 100 constituents 🔹 Linked streamflow, forcing & attributes
Links in 🧵
We've expanded the Caravan framework to bridge the gap between water quantity and quality.
This new open dataset features: 🔹 ~70M observations 🔹137k stations 🔹 100 constituents 🔹 Linked streamflow, forcing & attributes
Links in 🧵
December 18, 2025 at 8:00 AM
Excited to unveil Caravan-Qual! 🌊
We've expanded the Caravan framework to bridge the gap between water quantity and quality.
This new open dataset features: 🔹 ~70M observations 🔹137k stations 🔹 100 constituents 🔹 Linked streamflow, forcing & attributes
Links in 🧵
We've expanded the Caravan framework to bridge the gap between water quantity and quality.
This new open dataset features: 🔹 ~70M observations 🔹137k stations 🔹 100 constituents 🔹 Linked streamflow, forcing & attributes
Links in 🧵
Reposted by John Hammond
Happening this morning! Run don’t walk to room 228-230 to hear @zhaozhechen.bsky.social talk hydroclimate-ET synchrony!! @agu.org
Postdoc @zhaozhechen.bsky.social is representing our Powell Center ecosystem synchrony group at AGU this year! Come check out his Thursday 10:52 AM talk (abstract 1882146) in rm 228-230! it’s all about hydroclimatic and critical zone synchrony with/drivers of evapotranspiration.
December 18, 2025 at 2:56 PM
Happening this morning! Run don’t walk to room 228-230 to hear @zhaozhechen.bsky.social talk hydroclimate-ET synchrony!! @agu.org
Reposted by John Hammond
In case you missed it live, a full recording of my rapid-response livestream regarding news surrounding the proposed imminent and sudden dismantling of the National Center for Atmospheric Research (NCAR) is now available.
Special rapid response stream re: proposed dismantling of National Center for Atmospheric Research
The latest in a recurring series of live, virtual, & interactive "office hours" hosted by Dr. Daniel Swain on various topics related to extreme #weather and #climate. 12/17/2025 topic: This will be a special emergency livestream to discuss the context and broader implications of breaking news last n
youtu.be
December 17, 2025 at 6:49 PM
In case you missed it live, a full recording of my rapid-response livestream regarding news surrounding the proposed imminent and sudden dismantling of the National Center for Atmospheric Research (NCAR) is now available.
Reposted by John Hammond
Another example - from just today - of excellent and essential climate and weather research from @ncar-ucar.bsky.social with clear impacts on flood-prone communities
doi.org/10.1038/s432... #NCAR
doi.org/10.1038/s432... #NCAR
Moisture from US Corn Belt fuels more intense convective storms - Communications Earth & Environment
The groundwater-crop-irrigation interactions across the US Corn Belt amplify convective storm frequency, extend storm lifetime, and accelerate storm movement, based on a high-resolution regional clima...
doi.org
December 17, 2025 at 10:49 PM
Another example - from just today - of excellent and essential climate and weather research from @ncar-ucar.bsky.social with clear impacts on flood-prone communities
doi.org/10.1038/s432... #NCAR
doi.org/10.1038/s432... #NCAR
Reposted by John Hammond
I 'll have a special rapid-response livestream for 8:30am PT today to discuss dire implications of this proposal to dismantle NCAR. Due to extreme fire weather in Boulder today (and associated pre-emptive power outages/NCAR closure), I am going live ASAP. www.youtube.com/live/FTKW68R...
December 17, 2025 at 3:50 PM
I 'll have a special rapid-response livestream for 8:30am PT today to discuss dire implications of this proposal to dismantle NCAR. Due to extreme fire weather in Boulder today (and associated pre-emptive power outages/NCAR closure), I am going live ASAP. www.youtube.com/live/FTKW68R...
Reposted by John Hammond
The latest UK Hydrological Summary has been published 🌧️
November was UK's wettest month so far in 2025 & many areas have shifted from drought concerns to flood risk.
Groundwater levels notably low and reservoir levels still below average in parts. Winter rainfall amount will be crucial.
🧪 1/
November was UK's wettest month so far in 2025 & many areas have shifted from drought concerns to flood risk.
Groundwater levels notably low and reservoir levels still below average in parts. Winter rainfall amount will be crucial.
🧪 1/
December 17, 2025 at 9:26 AM
The latest UK Hydrological Summary has been published 🌧️
November was UK's wettest month so far in 2025 & many areas have shifted from drought concerns to flood risk.
Groundwater levels notably low and reservoir levels still below average in parts. Winter rainfall amount will be crucial.
🧪 1/
November was UK's wettest month so far in 2025 & many areas have shifted from drought concerns to flood risk.
Groundwater levels notably low and reservoir levels still below average in parts. Winter rainfall amount will be crucial.
🧪 1/
Photos from the Patapsco River in Maryland yesterday. Lucky to have the snow stick to the trees despite the high winds! #riversfromabove
December 15, 2025 at 9:27 PM
Photos from the Patapsco River in Maryland yesterday. Lucky to have the snow stick to the trees despite the high winds! #riversfromabove
Reposted by John Hammond
The fact that parts of Washington are seeing record-breaking flooding this week is not surprising given that 1) many locations saw record 24hr precipitation (well above 100yr ARI) & 2) near-record temperatures *simultaneously* (no snow in mtns, so all precip became runoff). #WAwx
December 12, 2025 at 12:32 AM
The fact that parts of Washington are seeing record-breaking flooding this week is not surprising given that 1) many locations saw record 24hr precipitation (well above 100yr ARI) & 2) near-record temperatures *simultaneously* (no snow in mtns, so all precip became runoff). #WAwx
Reposted by John Hammond
A powerful atmospheric river has drenched Washington state with nearly 5 trillion gallons of rain over the past week. The deluge is linked to warm water and air, along with unusual weather conditions tracing back to tropical cyclone flooding in Indonesia.
Blend of unusual weather conditions brings trillions of gallons in persistent rain to the Northwest
A powerful atmospheric river has drenched Washington state with nearly 5 trillion gallons of rain over the past week.
bit.ly
December 11, 2025 at 10:30 AM
A powerful atmospheric river has drenched Washington state with nearly 5 trillion gallons of rain over the past week. The deluge is linked to warm water and air, along with unusual weather conditions tracing back to tropical cyclone flooding in Indonesia.
Sand bag deployment and flood as seen from USGS High Vis camera in Everson, WA
apps.usgs.gov/hivis/camera...
apps.usgs.gov/hivis/camera...
December 11, 2025 at 3:53 AM
Sand bag deployment and flood as seen from USGS High Vis camera in Everson, WA
apps.usgs.gov/hivis/camera...
apps.usgs.gov/hivis/camera...
Reposted by John Hammond
Officials warned of “locally catastrophic” river flooding in Washington state Wednesday amid a major atmospheric river storm that was poised to drop 20 inches of rain in the Cascade Range.
Two rivers north of Seattle, the Snohomish and Skagit rivers, were predicted to crest at record levels.
Two rivers north of Seattle, the Snohomish and Skagit rivers, were predicted to crest at record levels.
Atmospheric river dumping 20 inches of rain on West Coast mountain range
Dozens of rivers were forecast to spill their banks across the Pacific Northwest, as Washington state braced for its worst flooding in at least 16 years.
www.sfchronicle.com
December 10, 2025 at 9:14 PM
Officials warned of “locally catastrophic” river flooding in Washington state Wednesday amid a major atmospheric river storm that was poised to drop 20 inches of rain in the Cascade Range.
Two rivers north of Seattle, the Snohomish and Skagit rivers, were predicted to crest at record levels.
Two rivers north of Seattle, the Snohomish and Skagit rivers, were predicted to crest at record levels.