Jaime Kostelnik

Wildfire often amplifies the likelihood and magnitude of debris flows in steep terrain. In arid climates (e.g. US Mountain West and Southwest), post-fire debris flows typically occur during the first rains following fire, suggesting that rainfall-driven erosion is a strong control on in-channel preconditioning and triggering of these hazards.

When a landslide is recognized to be life-threatening, difficult decisions follow. Like, should the house be evacuated? Is the community safe enough? How much should be invested in mitigation? For the past two decades, we have been applying a quantitative risk management framework to inform these types of decisions.

The development of a Geologic Hazards Program for the USDA Forest Service is a challenging undertaking.

A range of flow types can be observed in steep, recently-burned terrain, but predicting the spatial distribution of debris flows resulting from a single storm event remains challenging.

Optical remote sensing observations of the 2019 Ridgecrest, California, earthquake sequence revealed a significant amount of surface ejecta in the nearby Searles Lake, including one area where the surface ejecta was arranged in a repeating hexagonal “honeycomb” pattern.

In the mid-1980s, Art Schultz (USGS, ret.) drew on experiences in the Colorado Front Range to identify numerous large, stratigraphically intact, kilometer-scale bedrock landslides on interbedded sandstone-shale dip slopes in the Virginia Valley and Ridge.

Wyoming’s diverse topography is host to a wide range of landslide types, density, and susceptibility. Landslides are common in multiple regions of the state, and several high-profile events in the past decade have damaged property, disrupted transportation corridors, and led to substantial economic loss.

The recently published landslide inventory for most landslide-prone areas in Minnesota provides the basis for generation of landslide susceptibility maps. These maps are derived from logistic regression analysis of mapped landslide occurrences, terrain characteristics, and Quaternary geological mapping.

Post-fire debris flows are often observed during the first rainy season following a wildfire, but it is unclear how long the elevated threat of debris flow persists. We constrained a hydrologic model using field and remotely sensed measurements of soil-infiltration capacity, vegetation cover, runoff, and debris-flow activity.

Heavy rainfall on the afternoon of August 3, 2022 triggered a debris flow in the Hermits Peak-Calf Canyon burn area.  A USGS monitoring station installed in the drainage basin captured video footage of the flow.  This clip of the video shows the flow from 13:43:00 MDT to 13:45:32 MDT.

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During the late Oligocene to early Miocene, the Marysvale volcanic field of southwestern Utah experienced three consecutive, catastrophic, mega-scale collapse events: the Sevier, Markagunt, and Black Mountains gravity slides, which we refer to collectively as the Marysvale gravity slide complex (MGSC).

Landslides display a broad spectrum of speeds for incompletely known reasons. Sliding occurs along slickensided undulatory shear surfaces within boundary shear gouge comprising clay mineral and non-clay (granular) particle mixtures, similar to tectonic fault gouge.

During September 2017, Hurricane Maria triggered >70,000 slope failures throughout the mountainous regions of Puerto Rico (USA). Since then, the USGS has had a multi-faceted team working to understand landslide hazards in Puerto Rico.

Building and maintaining a landslide hazards program as a state agency presents many opportunities and challenges.

Calwood burn area, Heil Ranch post-fire debris-flow monitoring station video footage from rainstorm on July 31, 2021 from 14:07 MDT to 14:13:11 MDT.

Calwood burn area, Calwood post-fire debris-flow monitoring station video footage from rainstorm on July 31, 2021 from 14:06 MDT to 14:13:05 MDT.