Peter Griffiths
Mr. Peter Griffiths is the Regional Director for the Rocky Mountain Region at the United States Geological Survey (USGS).
Mr. Griffiths is responsible for the scientific and operational leadership of 1,000 employees in nine USGS science centers across the states of the Upper Colorado Basin (DOI Region 7): Colorado, New Mexico, Utah, and Wyoming. This workforce is engaged in a broad range of hydrologic, geologic, and biological sciences regionally, nationally, and internationally, including: hydrologic research and data collection; minerals and energy resources assessments and research; land change science, geologic mapping, and Uncrewed Aerial Systems applications and development; earthquake, landslide, and geomagnetic hazard monitoring and research; invasive and trust species research; social and economic analysis and decision support science and tools for natural resource management; and nuclear science in support of geologic and biological sciences.
Mr. Griffiths joined the USGS in 1991, as a Hydrologic Aide with the National Research Program (NRP) of the Water Mission Area (WMA) in Tucson, AZ. Serving the NRP as a Hydrologic Technician, Hydrologist, and Research Hydrologist, Mr. Griffiths conducted research on mass-movement and sediment transport in the southwestern United States, with a focus on the frequency, processes of initiation, and geomorphic impact of debris flows in canyon rivers of the Colorado Plateau. In 2009, Mr. Griffiths moved to Denver, CO, to serve as the Assistant Chief for the NRP Central Branch, then joined the Southwest Region as Deputy Regional Director in 2015. He was selected as the Regional Director for the Rocky Mountain Region in 2022.
Mr. Griffiths is a graduate of the University of Arizona, where he earned his Master of Science in Geosciences with a Minor in Hydrology. He earned his Bachelor of Arts Degree in Archeological Studies from Yale University.
Science and Products
Filter Total Items: 33
The use of the multi-dimensional surface-water modeling system (MD-SWMS) in calculating discharge and sediment transport in remote ephemeral streams
No abstract available.
Authors
Peter G. Griffiths, David J. Topping, Richard R. McDonald, Thomas A. Sabol
Analyzing debris flows with the statistically calibrated empirical model LAHARZ in southeastern Arizona, USA
Hazard-zone delineation for extreme events is essential for floodplain management near mountain fronts in arid and semiarid regions. On 31 July 2006, unprecedented debris flows occurred in the Santa Catalina Mountains of southeastern Arizona following extreme multiday precipitation (recurrence interval > 1000 years for 4-day precipitation). Most mobilized sediment contributing to debris flows was
Authors
Christopher S. Magirl, Peter G. Griffiths, Robert H. Webb
Plants and ventifacts delineate late Holocene wind vectors in the Coachella Valley, USA
Strong westerly winds that emanate from San Gorgonio Pass, the lowest point between Palm Springs and Los Angeles, California, dominate aeolian transport in the Coachella Valley of the western Sonoran Desert. These winds deposit sand in coppice dunes that are critical habitat for several species, including the state and federally listed threatened species Uma inornata, a lizard. Although wind direc
Authors
Peter G. Griffiths, R. H. Webb, M. Fisher, Allan Muth
Spatial distribution and frequency of precipitation during an extreme event: July 2006 mesoscale convective complexes and floods in southeastern Arizona
An extreme, multiday rainfall event over southeastern Arizona during 27–31 July 2006 caused record flooding and a historically unprecedented number of slope failures and debris flows in the Santa Catalina Mountains north of Tucson. An unusual synoptic weather pattern induced repeated nocturnal mesoscale convective systems over southeastern Arizona for five continuous days, generating multiday rain
Authors
Peter G. Griffiths, Christopher S. Magirl, Robert H. Webb, Erik Pytlak, Peter A. Troch, Steve W. Lyon
Slopes fail, debris flows in extremis
No abstract available.
Authors
Robert Webb, Christopher S. Magirl, Peter G. Griffiths, Ann M. Youberg, Philip A Pearthree
Debris flows and floods in southeastern Arizona from extreme precipitation in July 2006 — Magnitude, frequency, and sediment delivery
From July 31 to August 1, 2006, an unusual set of atmospheric conditions aligned to produce record floods and an unprecedented number of slope failures and debris flows in southeastern Arizona. During the week leading up to the event, an upper-level low-pressure system centered over New Mexico generated widespread and locally heavy rainfall in southeastern Arizona, culminating in a series of stron
Authors
Robert H. Webb, Christopher S. Magirl, Peter G. Griffiths, Diane E. Boyer
Holocene debris flows on the Colorado Plateau: The influence of clay mineralogy and chemistry
Holocene debris flows do not occur uniformly on the Colorado Plateau province of North America. Debris flows occur in specific areas of the plateau, resulting in general from the combination of steep topography, intense convective precipitation, abundant poorly sorted material not stabilized by vegetation, and the exposure of certain fine-grained bedrock units in cliffs or in colluvium beneath tho
Authors
R. H. Webb, Peter G. Griffiths, L. P. Rudd
Modeling Water-Surface Elevations and Virtual Shorelines for the Colorado River in Grand Canyon, Arizona
Using widely-available software intended for modeling rivers, a new one-dimensional hydraulic model was developed for the Colorado River through Grand Canyon from Lees Ferry to Diamond Creek. Solving one-dimensional equations of energy and continuity, the model predicts stage for a known steady-state discharge at specific locations, or cross sections, along the river corridor. This model uses 2,68
Authors
Christopher S. Magirl, Michael J. Breedlove, Robert H. Webb, Peter G. Griffiths
Channel response to low-elevation desert fire: The King Valley Fire of 2005
In late September to early October 2005, a fire swept north from the Yuma Proving Grounds and into the Kofa National Wildlife Refuge (NWR), traveling mainly along desert wash systems and low-relief alluvial fans. This fire burned 9,975 ha, moving through xeroriparian systems in washes as well as low-elevation desert ecosystems in King Valley, a major area of designated wilderness in the southern p
Authors
Robert H. Webb, Peter G. Griffiths, Cynthia S.A. Wallace, Diane E. Boyer
Debris flows and record floods from extreme mesoscale convective thunderstorms over the Santa Catalina Mountains, Arizona
Ample geologic evidence indicates early Holocene and Pleistocene debris flows from the south side of the Santa Catalina Mountains north of Tucson, Arizona, but few records document historical events. On July 31, 2006, an unusual set of atmospheric conditions aligned to produce record floods and an unprecedented number of debris flows in the Santa Catalinas. During the week prior to the event, an u
Authors
Christopher S. Magirl, Craig Shoemaker, Robert H. Webb, Mike Schaffner, Peter G. Griffiths, Erik Pytlak
Impact of recent extreme Arizona storms
Heavy rainfall on 27–31 July 2006 led to record flooding and triggered an historically unprecedented number of debris flows in the Santa Catalina Mountains north of Tucson, Ariz. The U.S. Geological Survey (USGS) documented record floods along four watercourses in the Tucson basin, and at least 250 hillslope failures spawned damaging debris flows in an area where less than 10 small debris flows ha
Authors
C. S. Magirl, R. H. Webb, Peter G. Griffiths, M. Schaffner, C. Shoemaker, E. Pytlak, S. Yatheendradas, S. W. Lyon, Peter A. Troch, S. L. E. Desilets, D.C. Goodrich, C.L. Unkrich, Ann Youberg, P. A. Pearthree
ADV point measurements within rapids of the Colorado River in Grand Canyon
Rapids on the Colorado River in Grand Canyon attract over 20,000 white-water enthusiasts a year and are considered one of the premiere collections of rapids in North America. While this collection of rapids is an important recreational resource, relatively little is known of the specific hydraulics of individual rapids. Flow measurements are occasionally made in the low-velocity reaches between ra
Authors
Christopher S. Magirl, Peter G. Griffiths, Robert Webb
Science and Products
Filter Total Items: 33
The use of the multi-dimensional surface-water modeling system (MD-SWMS) in calculating discharge and sediment transport in remote ephemeral streams
No abstract available.
Authors
Peter G. Griffiths, David J. Topping, Richard R. McDonald, Thomas A. Sabol
Analyzing debris flows with the statistically calibrated empirical model LAHARZ in southeastern Arizona, USA
Hazard-zone delineation for extreme events is essential for floodplain management near mountain fronts in arid and semiarid regions. On 31 July 2006, unprecedented debris flows occurred in the Santa Catalina Mountains of southeastern Arizona following extreme multiday precipitation (recurrence interval > 1000 years for 4-day precipitation). Most mobilized sediment contributing to debris flows was
Authors
Christopher S. Magirl, Peter G. Griffiths, Robert H. Webb
Plants and ventifacts delineate late Holocene wind vectors in the Coachella Valley, USA
Strong westerly winds that emanate from San Gorgonio Pass, the lowest point between Palm Springs and Los Angeles, California, dominate aeolian transport in the Coachella Valley of the western Sonoran Desert. These winds deposit sand in coppice dunes that are critical habitat for several species, including the state and federally listed threatened species Uma inornata, a lizard. Although wind direc
Authors
Peter G. Griffiths, R. H. Webb, M. Fisher, Allan Muth
Spatial distribution and frequency of precipitation during an extreme event: July 2006 mesoscale convective complexes and floods in southeastern Arizona
An extreme, multiday rainfall event over southeastern Arizona during 27–31 July 2006 caused record flooding and a historically unprecedented number of slope failures and debris flows in the Santa Catalina Mountains north of Tucson. An unusual synoptic weather pattern induced repeated nocturnal mesoscale convective systems over southeastern Arizona for five continuous days, generating multiday rain
Authors
Peter G. Griffiths, Christopher S. Magirl, Robert H. Webb, Erik Pytlak, Peter A. Troch, Steve W. Lyon
Slopes fail, debris flows in extremis
No abstract available.
Authors
Robert Webb, Christopher S. Magirl, Peter G. Griffiths, Ann M. Youberg, Philip A Pearthree
Debris flows and floods in southeastern Arizona from extreme precipitation in July 2006 — Magnitude, frequency, and sediment delivery
From July 31 to August 1, 2006, an unusual set of atmospheric conditions aligned to produce record floods and an unprecedented number of slope failures and debris flows in southeastern Arizona. During the week leading up to the event, an upper-level low-pressure system centered over New Mexico generated widespread and locally heavy rainfall in southeastern Arizona, culminating in a series of stron
Authors
Robert H. Webb, Christopher S. Magirl, Peter G. Griffiths, Diane E. Boyer
Holocene debris flows on the Colorado Plateau: The influence of clay mineralogy and chemistry
Holocene debris flows do not occur uniformly on the Colorado Plateau province of North America. Debris flows occur in specific areas of the plateau, resulting in general from the combination of steep topography, intense convective precipitation, abundant poorly sorted material not stabilized by vegetation, and the exposure of certain fine-grained bedrock units in cliffs or in colluvium beneath tho
Authors
R. H. Webb, Peter G. Griffiths, L. P. Rudd
Modeling Water-Surface Elevations and Virtual Shorelines for the Colorado River in Grand Canyon, Arizona
Using widely-available software intended for modeling rivers, a new one-dimensional hydraulic model was developed for the Colorado River through Grand Canyon from Lees Ferry to Diamond Creek. Solving one-dimensional equations of energy and continuity, the model predicts stage for a known steady-state discharge at specific locations, or cross sections, along the river corridor. This model uses 2,68
Authors
Christopher S. Magirl, Michael J. Breedlove, Robert H. Webb, Peter G. Griffiths
Channel response to low-elevation desert fire: The King Valley Fire of 2005
In late September to early October 2005, a fire swept north from the Yuma Proving Grounds and into the Kofa National Wildlife Refuge (NWR), traveling mainly along desert wash systems and low-relief alluvial fans. This fire burned 9,975 ha, moving through xeroriparian systems in washes as well as low-elevation desert ecosystems in King Valley, a major area of designated wilderness in the southern p
Authors
Robert H. Webb, Peter G. Griffiths, Cynthia S.A. Wallace, Diane E. Boyer
Debris flows and record floods from extreme mesoscale convective thunderstorms over the Santa Catalina Mountains, Arizona
Ample geologic evidence indicates early Holocene and Pleistocene debris flows from the south side of the Santa Catalina Mountains north of Tucson, Arizona, but few records document historical events. On July 31, 2006, an unusual set of atmospheric conditions aligned to produce record floods and an unprecedented number of debris flows in the Santa Catalinas. During the week prior to the event, an u
Authors
Christopher S. Magirl, Craig Shoemaker, Robert H. Webb, Mike Schaffner, Peter G. Griffiths, Erik Pytlak
Impact of recent extreme Arizona storms
Heavy rainfall on 27–31 July 2006 led to record flooding and triggered an historically unprecedented number of debris flows in the Santa Catalina Mountains north of Tucson, Ariz. The U.S. Geological Survey (USGS) documented record floods along four watercourses in the Tucson basin, and at least 250 hillslope failures spawned damaging debris flows in an area where less than 10 small debris flows ha
Authors
C. S. Magirl, R. H. Webb, Peter G. Griffiths, M. Schaffner, C. Shoemaker, E. Pytlak, S. Yatheendradas, S. W. Lyon, Peter A. Troch, S. L. E. Desilets, D.C. Goodrich, C.L. Unkrich, Ann Youberg, P. A. Pearthree
ADV point measurements within rapids of the Colorado River in Grand Canyon
Rapids on the Colorado River in Grand Canyon attract over 20,000 white-water enthusiasts a year and are considered one of the premiere collections of rapids in North America. While this collection of rapids is an important recreational resource, relatively little is known of the specific hydraulics of individual rapids. Flow measurements are occasionally made in the low-velocity reaches between ra
Authors
Christopher S. Magirl, Peter G. Griffiths, Robert Webb