John Hammond

Guadalupe River flood: How to help and how to find help Several groups have mobilized to offer assistance to people affected by the Guadalupe River floods.

Several groups have mobilized to offer assistance to people affected by the Guadalupe River floods. via @texaspublicradio.bsky.social

Very busy Thursday for the group at #EGU25 ☀️🌊🤪 #floods #droughts

Quinn Miller’s MS work is now out! onlinelibrary.wiley.com/doi/10.1002/...

“Groundwater dominates snowmelt runoff and controls streamflow efficiency in the western United States” www.nature.com/articles/s43...

“ROBIN: Reference observatory of basins for international hydrological climate change detection” www.nature.com/articles/s41...

“What is a drought-to-flood transition? Pitfalls and recommendations for defining consecutive hydrological extreme events”
egusphere.copernicus.org/preprints/20...

Patterns in the delineation points show a significant use in areas near cities and along transportation corridors. The median basin delineated in StreamStats over the last year is 2 square miles and number of delineations totaled 605,106.

StreamStats Delineations - Where are they?
This figure shows the density of delineations per 25 square kilometer grid for all delineations over the period 3/16/24-3/15/25. www.usgs.gov/media/images...

Global patterns in observed hydrologic processes - Nature Water This study presents a global, searchable database of 400 research watersheds with published descriptions of dominant hydrologic flow pathways, supporting efficient hypothesis testing to investigate em...

New paper! After much work by me and my students we created a global database of hundreds of research watersheds, and perceptual models of their hydrologic processes. We use the data to test classic theories on how climate and landscape control dominant processes. www.nature.com/articles/s44...

The Role of Lithology on Concentration‐Discharge Relationships and Carbon Export in Two Adjacent Headwater Catchments Bedrock lithology drives differences in streamflow and carbon export in adjacent catchments, controlling variability in shallow flow paths Both catchments display similar in-stream major ion conc...

Latest paper out of the WS hydrology lab! Here we show spatial variability in lithology is important for streamflow behavior and carbon export, but geogenic solute export behavior is similar. agupubs.onlinelibrary.wiley.com/doi/full/10....

Hydrology Paper of the Day @margaretzimmer.bsky.social on how subsurface geology influences discharge and transport processes in two headwater catchments of the Diablo Range, California affected by wildfire: sedimentary and mélange lithologies, and understanding spatiotemporal DOC export.

Global patterns in observed hydrologic processes - Nature Water This study presents a global, searchable database of 400 research watersheds with published descriptions of dominant hydrologic flow pathways, supporting efficient hypothesis testing to investigate em...

“Global patterns in observed hydrologic processes” @mcmillanhydro.bsky.social @rarakihydro.bsky.social @jansei.bsky.social www.nature.com/articles/s44...

“Linking wetlands to relatively permanent flowing waters: a conterminous United States geospatial analysis” - 79% or 66% of freshwater palustrine wetlands are potentially connected to the stream network, depending if inclusive,exclusive flow permanence network used

link.springer.com/article/10.1...

“A low-cost approach to monitoring streamflow dynamics in small, headwater streams using timelapse imagery and a deep learning model” egusphere.copernicus.org/preprints/20...

Special thanks to James McNamara for guidance on this commentary, and to @manuelaibrunner.bsky.social for their insight and indispensable contributions to this paper. Keep an eye out for research on this topic from all coauthors, and we hope you join the quest to better understand this phenomenon!

Figure 1. Hydrological intensification, hydrological extreme transitions, and a sub-seasonal subset of hydrological extreme transitions we propose terming hydrological whiplash illustrated by (a) spatial and temporal scale, and (b–d) through time. Lines in panel b are meant to show the direction and not rate of trend and are informed by: Precipitation event intensity—Ficklin et al. (2022), dry spell length—Madakumbura et al. (2019), snow season length—Mudryk et al. (2020).

Figure 2. Questions water management decision makers may confront related to sub-seasonal hydrological extreme transitions categorised by temporal (a) and spatial (b) scale. While hydrological whiplash is specifically a sub-seasonal phenomenon, rapid transitions between floods and droughts can impact water management decisions even at annual to decadal scales.

Figure 3. Sub-seasonal hydrological extreme transitions in recent years illustrated using threshold definitions similar to those from Götte and Brunner (2024). Note that Götte and Brunner (2024) use a smoothed time series to identify drought, while a non-smoothed streamflow time series is shown in the panels above. While Götte and Brunner (2024) focused on drought-to-flood transitions, we also show a flood-to-drought example here. Discharge data associated with U.S. Geological Survey (USGS) streamgages are available from the U.S. Geological Survey National Water Information System (2025).

We (1) describe hydrological intensification and whiplash impacts, (2) introduce complexities in quantifying transitions, (3) discuss the processes controlling transitions and trends, (4) discuss considerations involved in modelling these transitions, (5) suggest priority research questions

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...

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....

New paper from our group about something we do for a while but never took the time to publish.

What can you do with missing data in deep learning based hydro models?

Also I want to boost @gauchm.bsky.social. Welcome to BlueSky!

Link to preprint, code and results in his thread.

Photo of alpine mountain tops ribboned with snow and a lake in the valley below.

New research from our faculty Kate Hale (@katehale.bsky.social) and Vrije Universiteit Amsterdam’s Wouter Berghuijs shows how climate change affects river flows in snowy regions across the Northern Hemisphere.

Learn more in the Nature publication: www.nature.com/articles/s41...

The snow drought in the southwest could lead to lower and earlier peak and low flows, a longer duration at low flow, and lower runoff efficiency: www.tandfonline.com/doi/full/10....

Prioritization of Research on Drought Assessment in a Changing Climate Climate change adds conceptual and quantitative challenges to traditional drought assessments Reducing the sensitivity of drought indicators to non-stationarity is essential for accurately assess...

-Climate change challenges traditional drought assessments
-Reducing the sensitivity of drought indicators to non-stationarity is essential for accurately assessing drought
-Multiple drought definitions or concepts are possible, and needed, to correctly assess drought in a changing climate

Great interview by @climateadam.bsky.social who never shies away from asking scientists the tough questions about how we FEEL ⬇️

@cleanetwork.bsky.social welcome, so glad to see you here! I just added you to this starter pack, where you will find many kindred spirits.

Welcome to the Bluesky account for Stand Up for Science 2025!

Keep an eye on this space for updates, event information, and ways to get involved. We can't wait to see everyone #standupforscience2025 on March 7th, both in DC and locations nationwide!

#scienceforall #sciencenotsilence

New Predictors for Hydrologic Signatures: Wetlands and Geologic Age Across Continental Scales This article contributes to the longstanding effort to use landscape metrics to predict streamflow dynamics. We introduce two new metrics describing wetlands and geologic age and use random forests t....

Amongst all of this, our students are still publishing excellent papers. My recent Masters student Annie Holt, now at NWS, shows how geologic age and (region-dependent) wetland fraction metrics can be used to improve our predictions of baseflow in watersheds across the U.S.: doi.org/10.1002/hyp....

Even more to explore!

A few more:

There’s so much fantastic information in this report for those in #sciencecommunication and #teaching, not to mention for all us water users and water enthusiasts!

This!!!! The USGS just released the first National Water Availability Assessment report: pubs.usgs.gov/publication/.... Going to highlight some of my favorite figures after skimming the report and the corresponding #USGSvizlab sites water.usgs.gov/vizlab/water... for the first time in this thread.

Stylized illustration of the water cycle of the lower 48 United States, showing the fate of water that enters through precipitation. Most of the water returns to the atmosphere through evapotranspiration, but much of the water ends up in the Atlantic and Pacific Oceans, in Canada, or in the Gulf of Mexico through streamflow.

Map of water limitation in the lower 48 United States by watershed. Areas with relatively high water limitation are in the high plains, Texas, California, and the Mississippi Embayment hydrologic regions.

The U.S. Geological Survey (USGS) Vizlab has just released a new, interactive data visualization website about the USGS National Water Availability Assessment Report and Data Companion. Explore the data and the key findings of the assessment at water.usgs.gov/vizlab/water... #DataViz #rstats #USGS