Current Organizations / Institutes

The organizations/institutes from the scholar's latest article

Previous Organizations / Institutes

The organizations / institutes from the scholar's other articles in the past ten years


Jordy Hendrikx has a total of 462 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Antarctica InSync Science Plan

    by Stefanie Arndt, Alexander Haumann, Antje Boetius, Signe Aaboe, Nerilie Abram, Nicoletta Ademollo, Franziska Aemisegger, Simon Alexander, David Amblas, Charles Amory, et al.

    Antarctica InSync is a global effort to synchronise research across Antarctica and the Southern Ocean, connecting ice, ocean, land, climate, and life to protect this vital region. This roadmap paper introduces the scientific and technological motivation and action plan to build an international programme for a coordinated field season in Antarctica and its surrounding seas. It lays out the international collaboration that is required to realise an ambitious action plan and the opportunities for the science community to address important scientific themes that identify current knowledge gaps. In the spirit of the Antarctic Treaty Consultative Meeting (ATCM), the planned scientific action mandates free data exchange, facilitates international collaboration, and derives expert scientific advice together with the Scientific Committee on Antarctic Research (SCAR). Aligned with challenges of the United Nation Ocean and Cryosphere Decades, we plan a shared global effort to better understand the role of Antarctica and its surrounding ocean for our global futures, building on decades of achievements in polar and ocean science. As a milestone leading up to the next International Polar Year in 2032/33 (IPY5), the ambition is to achieve a new level of cooperation, with opportunities for the next generation of polar scientists around the world by enhancing practices in sharing of ideas, infrastructure and information.

  • Introduction: Antarctica InSync – A Roadmap Towards an Internationally Coordinated, Circumpolar, and Year-Round Antarctic Mission

    by Stefanie Arndt, Alexander Haumann, Antje Boetius, Nerilie Abram, Carlo Barbante, Inga Beck, Nicole Biebow, Daan Blok, Maarten Boersma, Camilla Brekke, et al.

    Antarctica InSync is a global effort to synchronise research across Antarctica and the Southern Ocean, connecting ice, ocean, land, climate, and life to protect this vital region. This roadmap paper introduces the scientific and technological motivation and action plan to build an international programme for a coordinated field season in Antarctica and its surrounding seas. It lays out the international collaboration that is required to realise an ambitious action plan and the opportunities for the science community to address important scientific themes that identify current knowledge gaps. In the spirit of the Antarctic Treaty Consultative Meeting (ATCM), the planned scientific action mandates free data exchange, facilitates international collaboration, and derives expert scientific advice together with the Scientific Committee on Antarctic Research (SCAR). Aligned with challenges of the United Nation Ocean and Cryosphere Decades, we plan a shared global effort to better understand the role of Antarctica and its surrounding ocean for our global futures, building on decades of achievements in polar and ocean science. As a milestone leading up to the next International Polar Year in 2032/33 (IPY5), the ambition is to achieve a new level of cooperation, with opportunities for the next generation of polar scientists around the world by enhancing practices in sharing of ideas, infrastructure and information.

  • Open Access

    Challenges of Using Signaling Data From Telecom Network in Non-Urban Areas

    by Håvard Toft, Alexey Sirotkin, Markus Landrø, Rune Verpe Engeset, Jordy Hendrikx

    Outdoor recreation continues to increase in popularity. In Norway, several avalanche fatalities are recorded every year, but the accurate calculation of a fatal accident rate is impossible without knowing how many people are exposed. We attempted to employ signaling data from telecom network data to enumerate backcountry travelers in avalanche terrain. Each signaling data event contains information about which coverage area the phone is connected to and timestamp. There is no triangulation, making it impossible to know whether the associated phone is moving or stationary within the coverage area. Hence, it's easier to track the phone's movement through different coverage areas. We utilize this by enumerating the number of people with phones traveling to avalanche-prone terrain for the 2019/2020 winter season. We estimated that 13,666 phones were in avalanche terrain during the season, ranging from 0 to 118 phones/day with an average of 75 phones/day. We correlated the number of phones per day against amount of daylight (R2=0.186, p-value <0.01), weekends and holidays (R2=0.073, p-value <0.01), number of bulletin views (R2=0.045, p-value <0.01). Unfortunately, the validation revealed discrepancies between the estimated positions in the mobile network and the true reference positions as collected with a GPS. We attribute this to the algorithm being designed to measure urban mobility and the long distance between the base transceiver stations in mountainous areas. This lack of coherence between the signaling data and GPS records for rural areas in Norway has implication for the utility of signaling data outside of urban regions.


  • Perceptions Among Backcountry Skiers During the COVID-19 Pandemic: Avalanche Safety and Backcountry Habits of New and Established Skiers

    by Esteban A. Valle, Andrew P. Cobourn, Spencer Jh. Trivitt, Jordy Hendrikx, Jerry D. Johnson, David C. Fiore

    Introduction: The coronavirus disease 2019 (COVID-19) pandemic impacted the ski industry worldwide by closing or limiting access to ski resorts. Subsequently, anecdotal reports of increased backcountry use emerged in the press, with concerns of inexperienced skiers causing or having problems in the backcountry. This study attempted to quantify this and identify motivations for new backcountry skiers. Methods: Self-identified backcountry skiers and snowboarders (aged ≥18 y) in the United States and Canada completed an anonymous 29-question online survey distributed by regional avalanche centers, education providers, and skiing organizations (n =4792). Respondents were stratified by backcountry experience, defining “newcomers” who began backcountry skiing from 2019 to 2021, coincident with the COVID-19 pandemic. Percentages of ski days spent in the backcountry were compared before and during the COVID-19 pandemic using paired t-tests and across cohorts using repeated-measures analysis of variance. Avalanche education was compared using unpaired χ2 tests. Results: Of established skiers, 81% noticed more people in the backcountry and 27% reported increasing their own use. Participants reported spending 17% (95% CI, 15.8–17.9) more of their days in the backcountry during the COVID-19 pandemic, with newcomers increasing their time spent by 36% and established skiers increasing their time spent by 13% ( P<0.0001). Of newcomers, 27% cited the COVID-19 pandemic as motivation to enter the backcountry and 24% lacked formal avalanche education, which is significantly higher than the 14% of established skiers ( P<0.0001). Conclusions: Influenced by factors related to COVID-19, reported backcountry use increased during the pandemic. Newcomers had a lower level of avalanche education and less confidence in evaluating terrain. Because 80% of participants were recruited from avalanche safety or education websites, this likely underestimates skiers lacking avalanche awareness or education and is further limited by the nature of online surveys.


  • Open Access

    The Impact of Avalanche Education on Risk Perception, Confidence, and Decision-Making among Backcountry Skiers

    by Kaylin Greene, Jordy Hendrikx, Jerry Johnson

    With the burgeoning popularity of winter backcountry leisure, there has been an increased interest in implementing education to prevent avalanche related accidents. Yet little research has explored whether avalanche education actually improves avalanche risk awareness. The current study examined why participants enrolled in avalanche education, what they learned, and whether participation led to changes in risk perceptions, risk perception confidence, and decision-making. Backcountry skiers and snowboarders enrolled in an introductory avalanche course in Montana (N = 184, 47.28% female) completed surveys before and after the course that included randomized photos of regional avalanche terrain. Multi-level models demonstrated that participants became more conservative in their risk perceptions and their stated willingness to ski uncertain terrain between pre- and post-test. Perception confidence increased, with larger gains for women, novices, and risk averse skiers. The results provide preliminary evidence that avalanche education may impact risk perceptions and provide useful hands-on skills for winter backcountry recreationalists.


  • Open Access

    An Operational Methodology for Validating Satellite-Based Snow Albedo Measurements Using a UAV

    by Andrew Mullen, Eric A. Sproles, Jordy Hendrikx, Joseph A. Shaw, Charles K. Gatebe

    Snow albedo is highly variable over multiple temporal and spatial scales. This variability is more pronounced in areas that experience seasonal snowpack. Satellite retrievals, physically based models and parameterizations for snow albedo all require ground-based measurements for calibration, initialization, and validation. Ground measurements are generally made using upward and downward-facing pyranometers at opportunistically located weather stations that are sparsely distributed, particularly in mountainous regions. These station-based measurements cannot capture the spatial variability of albedo across the land surface. Uncrewed Aerial Vehicles (UAVs) equipped with upward and downward-facing pyranometers provide near-surface measurements of broadband albedo that are spatially distributed across landscapes, offering improvements over in-situ sensors. At the hillslope to watershed scale albedo measurements from UAVs taken over heterogeneous terrain are a function of the spatial variability in albedo and topography within the downward-facing sensor’s field-of-view (FOV). In this research we propose methods for topographic correction of UAV snow albedo measurements and comparison to gridded satellite albedo products. These methods account for the variability of surface topography and albedo within the sensor FOV, sensor tilt, and the angular response of pyranometers. We applied the proposed methodologies to UAV snow albedo measurements collected over an alpine meadow in southwest Montana, United States (45.23°, −111.28°). Sensitivity analyses were conducted to determine the effect of altering the processing FOV (PFOV) for both topographic corrections and comparison to coincident Landsat 8-derived albedo measurements. Validation from ground-based albedo measurements showed the topographic correction to reduce albedo measurement error considerably over mildly sloping terrain. Our sensitivity analyses demonstrated that outcomes from the topographic correction and satellite comparison are highly dependent on the specified PFOV. Based on field observations and analyses of UAV albedo measurements made at different altitudes, we provide guidelines for strategizing future UAV albedo surveys. This research presents considerable advances in the standardization of UAV-based albedo measurement. We establish the foundation for future research to utilize this platform to collect near-surface validation measurements over heterogeneous terrain with high accuracy and consistency.


  • Open Access

    Powder Fever and Its Impact on Decision-Making in Avalanche Terrain

    by Andrea Mannberg, Jordy Hendrikx, Jerry Johnson, Audun Hetland

    We examined the effect of emotions, associated with “powder fever”, on decision-making in avalanche terrain. Background: Skiing in avalanche terrain is a voluntary activity that exposes the participant to potentially fatal risk. Impaired decision-making in this context can therefore have devastating results, often with limited prior corrective feedback and learning opportunities. Previous research has suggested that arousal caused by emotions affects risk assessment and intentions to engage in risky behavior. We propose that powder fever may induce similar responses. Methods: We used the following two experimental methods: laboratory studies with visual visceral stimuli (ski movies) and a field study with real stimuli (skiing exciting terrain). We evaluated the effect of emotions on attention, risk assessment, and willingness to expose oneself and others to risk. Results: Both the laboratory studies and the field study showed that skiing-related stimuli had a relatively strong effect on reported emotions. However, we found very few significant effects on decision-making or assessment of risk. Conclusions: Skiing activities make people happier. However, despite the clear parallels to sexual arousal, powder fever does not appear to significantly impair decision-making in our study. More research on the effects of powder fewer on milder forms of risk-taking behavior is needed.


  • Should I judge safety or danger? Perceived risk depends on the question frame.

    by Matthew B. Stephensen, Christin Schulze, Markus Landrø, Jordy Hendrikx, Audun Hetland

    Linguistic polarity is a natural characteristic of judgments: Is that situation safe/dangerous? How difficult/easy was the task? Is that politician honest/dishonest? Across six studies (N = 1599), we tested how the qualitative frame of the question eliciting a risk judgment influenced risk perception and behavior intention. Using a series of hypothetical scenarios of skiing in avalanche terrain, experienced backcountry skiers judged either how safe or how dangerous each scenario was and indicated whether they would ski the scenario. Phrasing risk judgments in terms of safety elicited lower judged safety values, which in turn resulted in a lower likelihood of intending to ski the slope. The frame "safe" did not evoke a more positive assessment than the frame "danger" as might be expected under a valence-consistent or communication-driven framing effect. This seemingly paradoxical direction of the effect suggests that the question frame directed attention in a way that guided selective information sampling. Uncertainty was not required for this effect as it was observed when judging objectively safe, uncertain, and dangerous scenarios. These findings advance our theoretical understanding of framing effects and can inform the development of practices that harness question framing for applied risk perception and communication. (PsycInfo Database Record (c) 2021 APA, all rights reserved).


  • Open Access

    An operational methodology for validating satellite-based snow albedo measurements using a UAV

    by Andrew Mullen, Eric A. Sproles, Jordy Hendrikx, Joseph A. Shaw, Charles K. Gatebe