Winter Hazards Research Articles

Could an extremely cold central European winter such as 1963 happen again despite climate change?

Abstract. Central European winters have warmed markedly since the mid-20th century. Yet cold winters are still associated with severe societal impacts on energy systems, infrastructure, and public health. It is therefore crucial to anticipate storylines of worst-case cold winter conditions and to understand whether an extremely cold winter, such as the coldest winter on the historical record of Germany in 1963 (−6.3 °C or −3.4σ seasonal December–January–February (DJF) temperature anomaly relative to 1981–2010), is still possible in a warming climate. Here, we first show based on multiple attribution methods that a winter of similar circulation conditions to 1963 would still lead to an extreme seasonal cold anomaly of about −4.9 to −4.7 °C (best estimates across methods) under present-day climate. This would rank as the second-coldest winter in the last 75 years. Second, we conceive storylines of worst-case cold winter conditions based on two independent rare event sampling methods (climate model boosting and empirical importance sampling): a winter as cold as 1963 is still physically possible in central Europe today, albeit very unlikely. While cold winter hazards become less frequent and less intense in a warming climate overall, it remains crucial to anticipate the possibility of an extremely cold winter to avoid potential maladaptation and increased vulnerability.

Investigating the occurrence of blizzard events over the contiguous United States using observations and climate projections

Over previous decades, the United States has been plagued by severe winter storms or blizzards, which caused millions of dollars in damages. However, the historical trend of blizzard events and the possible impacts of future global climate change on blizzard occurrences remain unclear. In this study, we analyzed historical blizzard occurrences using the observed storm event database, which shows that the Northern Plains, such as North Dakota, South Dakota, and Minnesota, had the most blizzard activities over the past 25 years. No significant trend in blizzard occurrence is found in those regions. When considering blizzards as compound events of strong wind and extreme snowfall, we estimated blizzard occurrences based on wind speed and snowfall in climate datasets, including Automated Surface Observing Systems wind speed, national gridded snowfall analysis, ERA5 reanalysis and historical simulations of 19 models in Coupled Model Intercomparison Project phase 6 (CMIP6), which show a good agreement with the observations with respect to the climatology of blizzard occurrence. In the near-term and long-term future under two emission scenarios, CMIP6 projections suggest decreases in both strong wind and extreme snowfall events, eventually leading to a significantly reduced frequency of compound events. Significant decreases in blizzard occurrence are found in the Northern Plains and Upper Midwest, suggesting potentially reducing the risk of winter hazards over those regions in a warming climate.

Winter Precipitation Type from Microwave Radiometers in New York State Mesonet Profiler Network

Abstract Winter precipitation is a major cause of vehicle accidents, aviation delays, school and business closures, injuries through slips and falls, and adverse health impacts such as cardiac arrests and deaths. However, an improved ability to monitor and predict winter precipitation type (p-type) could significantly reduce and mitigate these adverse impacts. This study presents and evaluates a modified parcel thickness method to derive p-type from a microwave radiometer (MWR) every 10 min. The MWR-retrieved p-types from six selected New York State Mesonet (NYSM) profiler network sites are validated against reference observations from the Meteorological Phenomena Idenfication Near the Ground (mPING) and Automated Surface Observing System (ASOS). Between the two reference observations, the mPING reports are biased toward snow (SN) and sleet (SLT) and away from rain (RA) and freezing rain (FZR) compared to the ASOS. The MWR has the best Pierce skill score (PSS) for RA, followed by SN, FZR, and SLT, and consistently overforecasts FZR and underforecasts SLT compared to both mPING and ASOS. The MWR p-type retrievals are generally found to be in better agreement with ASOS than mPING. Continuous thermodynamic profiles and p-type estimates from across all 17 profiler sites are available at http://www.nysmesonet.org/networks/profiler. Having such thermodynamic information from across the state can be a valuable resource, with a significant advantage over twice daily NWS radiosondes, for monitoring and tracking hazardous winter weather in real time, for accurate forecasting, and for issuing timely warnings and alerts. Significance Statement Accurate prediction and monitoring of winter precipitation type (p-type) is important due to the adverse economic and health impacts posed by winter weather. However, complexities in understanding and modeling the processes that govern p-type and inadequate observational data limit accurate monitoring and prediction. To address these issues, a ground-based microwave radiometer (MWR) that provides thermodynamic profiles up to 10 km every 2 min, as deployed at 17 sites in the New York State Mesonet (NYSM) profiler network, can be a valuable tool. This study evaluates the accuracy of p-type estimates based on the parcel thickness method from the MWR data and its implementation to the NYSM real-time operations.

Foundational Needs of Forecasters for Probabilistic Winter Forecasting

Abstract This study explores forecaster perceptions of emerging needs for probabilistic forecasting of winter weather hazards through a nationwide survey disseminated to National Weather Service (NWS) forecasters. Questions addressed four relevant thematic areas: 1) messaging timelines for specific hazards, 2) modeling needs, 3) current preparedness to interpret and communicate probabilistic winter information, and 4) winter forecasting tools. The results suggest that winter hazards are messaged on varying time scales that sometimes do not match the needs of stakeholders. Most participants responded favorably to the idea of incorporating new hazard-specific regional ensemble guidance to fill gaps in the winter forecasting process. Forecasters provided recommendations for ensemble run length and output frequencies that would be needed to capture individual winter hazards. Qualitatively, forecasters expressed more difficulties communicating, rather than interpreting, probabilistic winter hazard information. Differences in training and the need for social-science-driven practices were identified as a few of the drivers limiting forecasters’ ability to provide strategic winter messaging. In the future, forecasters are looking for new winter tools to address forecasting difficulties, enhance stakeholder partnerships, and also be useful to the local community. On the regional scale, an ensemble system could potentially accommodate these needs and provide specialized guidance on timing and sensitive/high-impact winter events. Significance Statement Probabilistic information gives forecasters the ability to see a range of potential outcomes so that they can know how much confidence to place in the forecast. In this study, we surveyed forecasters so that we can understand how the research community can support probabilistic forecasting in winter. We found that forecasters want new technologies that help them understand hard forecast situations, improve their communication skills, and that are useful to their local communities. Most forecasters feel comfortable interpreting probabilistic information, but sometimes are not sure how to communicate it to the public. We asked forecasters to share their recommendations for new weather models and tools and we provide an overview of how the research community can support probabilistic winter forecasting efforts.

Developing a Risk Assessment Model for a Highway Site during the Winter Season and Quantifying the Functional Loss in Terms of Traffic Reduction Caused by Winter Hazards Conditions

This paper introduces a methodology to quantify traffic change triggered by the combined effect of weather hazards based on winter weather hazards models. The winter weather hazards models for three vehicle types were developed with weigh-in-motion (WIM) data collected in the commuter highway in the cold Canadian region for 5 years. The developed model was utilized to simulate the variations of the percentage reduction for each vehicle type based on the 239 pairs of weather combinations composed of six cold categories and various amounts of snowfall. The first phase involved measuring the marginal effect of weather factors such as cold category (or temperature) on the percentage reduction in traffic volume. The second phase involved utilizing the same winter weather traffic model to quantify the effect of combined weather factors on the percentage reduction. The percentage reduction of the total traffic and passenger cars increased as temperature deteriorated and snowfall increased. Truck traffic decreased as snowfall increased, but interestingly, as temperature deteriorated, it was estimated that the truck traffic volume increased. This phenomenon assumed that truck traffic moves from low-maintenance to high-maintenance highways as the weather deteriorates. The methodology to quantify traffic volume changes can be adopted by highway agencies to determine the timing of the snowplow operation based on the risk assessed in terms of traffic volume reduction. It can also be used to predict the percentage reduction of traffic and then determine whether to open or close a highway.

Tracking decision-making of backcountry users using GPS tracks and participant surveys

Snow avalanches are a significant natural hazard representing the primary risk of death to backcountry travelers in many alpine countries. Careful use of backcountry terrain through effective decision making can mitigate the risk of dangerous snowpack conditions, but requires relevant knowledge and experience.We present the results from a large-scale crowd sourced data collection method from backcountry users. Using GPS tracking via a smartphone application, coupled with online surveys, we investigate the intersection of geographical complexity, backcountry experience, demographics and behavioral biases on decision-making while navigating hazardous winter terrain. We use data from 770 GPS tracks, representing almost 1.3 million GPS points, as a geographic expression of a group's resulting decisions, and use them to quantify and understand their decision-making process.Our analysis focuses on the change in terrain use as quantified using the Avalanche Terrain Exposure Scale (ATES), and time spent in avalanche terrain, as a function of experience, avalanche hazard and other group factors. We show that self-identified experts rate themselves as significantly more skilled and also had higher levels of avalanche education. Experts also had an increased exposure to avalanche terrain overall, and also more severe terrain, as represented by median time in class 3 ATES terrain.

Winter Climate Variability, De-Icing Salt and Streetside Tree Vitality

De-icing salts are applied to roads and walking surfaces to mitigate winter hazards resulting from ice, snow and freezing rain. The vitality of streetside trees, especially those growing in densely built urban areas, is compromised by repeated exposure to de-icing salts. Such trees already experience unfavorable establishment and growing conditions resulting from poor soil quality, inadequate moisture, physical abuse and air pollution−exposure to de-icing salt aggravates these challenges and can be an essential catalyst in tree mortality. Climate change is creating less predictable weather and, in some cases amplifying the intensity of winter storms. Cities that undertake snow and ice management may adopt modified approaches, and those less familiar with this practice may require its episodic adoption. We identify three pathways by which future climate warming may, counterintuitively, result in cities increasing their use of de-icing salt: (a) Warming winter temperatures in cities that were historically too cold to make effective use of sodium chloride (NaCl) for de-icing; (b) cities where daily high temperatures in winter may increase the frequency of freeze-thaw cycles; and, (c) cities in North America and Eurasia that may experience more severe winter weather resulting from greater variability in the circumpolar vortex (CPV). To offset potential damage to existing urban streetside trees and to ensure adequate soil and growing conditions for future trees, there is an immediate need for city foresters to collaborate with traffic safety and public works departments. We present a toolbox of approaches that can facilitate synchronized management efforts, including identifying the location of existing vulnerable trees and re-envisioning future infrastructure that would mitigate tree exposure to de-icing salts. At the same time, we call for the prioritization of research that investigates new potential pathways along which climate change may contribute to the novel adoption of de-icing salts.

Improvements to Lake-Effect Snow Forecasts Using a One-Way Air–Lake Model Coupling Approach

AbstractLake-effect convective snowstorms frequently produce high-impact, hazardous winter weather conditions downwind of the North American Great Lakes. During lake-effect snow events, the lake surfaces can cool rapidly, and in some cases, notable development of ice cover occurs. Such rapid changes in the lake-surface conditions are not accounted for in existing operational weather forecast models, such as the National Oceanic and Atmospheric Administration’s (NOAA) High-Resolution Rapid Refresh (HRRR) model, resulting in reduced performance of lake-effect snow forecasts. As a milestone to future implementations in the Great Lakes Operational Forecast System (GLOFS) and HRRR, this study examines the one-way linkage between the hydrodynamic-ice model [the Finite-Volume Community Ocean Model coupled with the unstructured grid version of the Los Alamos Sea Ice Model (FVCOM-CICE), the physical core model of GLOFS] and the atmospheric model [the Weather Research and Forecasting (WRF) Model, the physical core model of HRRR]. The realistic representation of lake-surface cooling and ice development or its fractional coverage during three lake-effect snow events was achieved by feeding the FVCOM-CICE simulated lake-surface conditions to WRF (using a regional configuration of HRRR), resulting in the improved simulation of the turbulent heat fluxes over the lakes and resulting snow water equivalent in the downwind areas. This study shows that the one-way coupling is a practical approach that is well suited to the operational environment, as it requires little to no increase in computational resources yet can result in improved forecasts of regional weather and lake conditions.

Modelling chronic winter hazards as a function of precipitation and temperature

In previous research, winter weather conditions like precipitation and cold were recognized as factors affecting the change in traffic volume, and a simulation has been conducted to model the effect of weather factor on variations in traffic flow. A winter weather hazard model considering natural chronic hazards in the winter season has been proposed. To achieve this purpose, this research formulated a dummy variable winter weather traffic model while considering explanatory variables such as expected daily volume, snowfall, and temperature. This model was derived using six-year traffic data that were collected on a weigh-in-motion site on Highway 44, in Alberta, Canada. Precipitation and cold data collected from a weather station were linked with traffic data to model traffic variations caused by weather factors. The performance of the model, on the ground of temporal transferability and model specification, was tested using data from different years. The temporal transferability test confirmed that the model can be successfully applied regardless of the year. It was also revealed that each vehicle class prefers a different model specification in estimating correct traffic volume.

Beyond “Snow Shoveler's Infarction”: Broadening perspectives on winter health risks

AbstractWinter constitutes a significant threat to humans via damages, injuries, and fatalities in mid and high latitude environments. Much of the research into the health impacts of winter centers on urban areas in the snow climates of North America. When considering how humans are vulnerable to winter hazards, the legend of Snow‐Shoveler's Infarction dominates the public's assessment of winter health risks. This article seeks to broaden the understanding of winter hazards by summarizing the diversity of impacts on human health including frostbite, hypothermia, traffic accidents, slips, and falls, unintentional carbon monoxide poisoning in addition to injuries, and fatalities associated with snow removal. Further, social determinants such as poverty and social isolation are identified as being associated with negative health outcomes. The disproportionate health impacts of winter are also summarized, thus revealing how some groups, particularly the disadvantaged, the elderly and those with preexisting health issues in urbanized snow climates of the United States and Canada, are more vulnerable to winter hazards.

Regional Thermodynamic Characteristics Distinguishing Long- and Short-Duration Freezing Rain Events over North America

Abstract Freezing rain is an especially hazardous winter weather phenomenon that remains particularly challenging to forecast. Here, we identify the salient thermodynamic characteristics distinguishing long-duration (six or more hours) freezing rain events from short-duration (2–4 h) events in three regions of the United States and Canada from 1979 to 2016. In the northeastern United States and southeastern Canada, strong surface cold-air advection is not common during freezing rain events. Colder onset temperatures at the surface and in the near-surface cold layer support longer-duration events there, allowing heating mechanisms (e.g., the release of latent heat of fusion when rain freezes at the surface) to act for longer periods before the surface reaches 0°C and precipitation transitions to rain. In the south-central United States, cold air at the surface is replenished via continuous cold-air advection, reducing the necessity of cold onset surface temperatures for event persistence. Instead, longer-duration events are associated with warmer and deeper >0°C warm layers aloft and stronger advection of warm and moist air into this layer, delaying its erosion via cooling mechanisms such as melting. Finally, in the southeastern United States, colder and especially drier onset conditions in the cold layer are associated with longer-duration events, with evaporative cooling crucial to maintaining the subfreezing surface temperatures necessary for freezing rain. Through an improved understanding of the regional conditions supporting freezing rain event persistence, we hope to provide useful information to forecasters in their attempt to predict these potentially damaging events.

Risk of Death and Major Injury from Natural Winter Hazards in Helicopter and Snowcat Skiing in Canada

Guests and guides partaking in helicopter and snowcat skiing (collectively known as mechanized skiing) are exposed to numerous natural winter hazards that can result in injury or death, but detailed quantitative risk estimates are currently lacking. This lack represents a considerable barrier for evaluating existing risk management practices and implementing evidence-based improvements. We collected historical incident and exposure information from mechanized skiing operations in Canada to perform a retrospective risk analysis. Our analysis dataset includes 713 incidents that resulted in injuries or fatalities among guests or guides during a total of 3,258,000 skier days from the 1970 to 2016 winter season. Overall risk of death from natural winter hazards in mechanized skiing was 18.6 fatalities per million skier days (1997-2016). Although the risk of death from avalanches decreased substantially over the entire study period, avalanches remain the largest contributor to the overall risk of death (77%), followed by tree wells and other non-avalanche-related snow immersions. The risk of death from avalanches in snowcat skiing is about half of that in helicopter skiing, but other snow immersion fatalities are more common. The risk of major injury to guests is primarily associated with other falls and collisions. The risk of major injury for guides is higher in snowcat skiing than in helicopter skiing. We recommend the design of an industry-wide incident and near-miss reporting system to support evidence-based improvements of safety practices.

It's cold out there

Companion AnimalVol. 24, No. 2 EditorialFree AccessIt's cold out thereDebra BourneDebra BourneSearch for more papers by this authorDebra BournePublished Online:6 Feb 2019https://doi.org/10.12968/coan.2019.24.2.65AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareShare onFacebookTwitterLinked InEmail The UK has a temperate climate — moderate, without the extreme heat or extreme cold experienced in many parts of the world. Despite that, we need to adapt our behaviour, clothing and local environment for improved comfort both in summer and in winter. This winter so far has been generally mild, but I cycled home through sleet yesterday evening and have needed to break the ice for the birds in my back garden (and remove the broken ice) several times recently — and that's in the London suburbs. Further periods of freezing weather, and snow in some areas, are forecast for the coming weeks.In the summer, the ‘Dogs Die in Hot Cars’ campaign was important to reduce the number of pets (mainly dogs) left alone in cars for ‘a few minutes’ — sufficient time to result in heatstroke. At this time of the year, it is important for owners to make sure that their pets are sufficiently protected from cold and wet (or snowy) conditions.It is particularly important to ensure that pets kept outdoors — whether cats, dogs, rabbits or other species — have adequate shelter and protection from cold temperatures, wind and precipitation At the same time, ventilation must be considered — outdoor bunnies provided with good insulation inside and/or outside their hutch still need to breathe! Additionally, owners may need to be reminded that water bowls and sipper bottles can freeze: water sources should be checked carefully at least twice a day in freezing weather and defrosted as necessary — remembering that simply breaking the ice is not enough, as it can re-freeze quickly. Food needs are also increased for all species in cold weather.For cats that live partly outdoors, a cat flap is highly beneficial to make sure cats can get indoors (but should be checked in case it has become stuck or blocked). An insulated cat kennel with blankets and perhaps a pet-safe microwaveable heat pad is a good back-up for indoor-outdoor cats and highly recommended if caring for a cat that lives mainly or totally outside. For dogs, care should be taken around ice-covered lakes, rivers etc. to avoid their going out onto the ice and falling in, and after walks, snow clumps, grit and salt should be removed from fur and feet.This is also the season to remind people of the hazard to their pets caused by antifreeze (Bates, 2016) and remind them to keep their antifreeze out of the reach of pets.Why am I telling you this, when I'm sure you are all familiar with this information? Unfortunately, every winter hypothermic pets, and animals with ethylene glucol poisoning, are presented to veterinary practices, so there is still a need to educate the pet-owning public on these matters, and we all need to think how best we can do that. Excellent advice on protecting pets from winter hazards is available from organisations such as the RSPCA, PDSA, Cats Protection, Dogs Trust and The Mayhew, so consider how to direct owners to these information sources, whether using your notice board, waiting room screens, leaflet racks and/or practice website, and make sure that information is available both electronically and in print.Finally, veterinary practices can do their bit for local wild birds in this weather by providing appropriate food and particularly by making sure that they have ice-free water available daily. References Bates N. Ethylene glycol poisoning. UK-Vet Companion Animal. 2016: 21(2):95–99. doi:https://doi.org/10.12968/coan.2016.21.2.95 Link, Google Scholar FiguresReferencesRelatedDetails 2 February 2019Volume 24Issue 2ISSN (print): 2053-0889ISSN (online): 2053-0897 Metrics History Published online 6 February 2019 Published in print 2 February 2019 Information© MA Healthcare LimitedPDF download

Crowdsourcing Snow Depth Data with Citizen Scientists

A new project harnesses the power of the winter backcountry recreation community to gather data that are vital to understanding snow, from winter hazards to water resources.

Investigating Safety Effectiveness of Wyoming Snow Fence Installations Along a Rural Mountainous Freeway

Drifting and blowing snow is a problematic and dangerous aspect of Interstate travel in the state of Wyoming. The control of snow and the maintenance of roadways is an essential and significant task for many state and local agencies. Many significant factors—such as vehicle control, surface conditions, and visibility—can be affected by hazardous winter weather. In areas such as the inspected 19-mi section of Interstate 80, snow fences have become a common and practical method of mitigating the problems caused by large quantities of snow near or on the traveled way. Wyoming deals with a high rate of adverse weather–related crashes during the winter season. Naive before–after analyses of snow fence installations have historically indicated a slight decrease in such crashes. In this study, the safety effectiveness of snow fence installations was investigated; more rigorous quantitative-based approaches were used and included a before–after analysis with empirical Bayes—in which Wyoming-specific safety performance functions were used—and odds ratio analyses. Crash modification factors were estimated for various crash types and severity levels. The results from this study indicate that the installation of snow fences contributes to a significant increase in the safety effectiveness of Interstate use during the winter. Specifically, it was found that during adverse weather conditions, snow fences decreased total crashes and fatal and injury crashes by about 25% and 62%, respectively.

WHITE – Winter hazards in terminal environment: An automated nowcasting system for Munich Airport

Winter weather is a decisive factor affecting the daily course of action at airports and causing delays or even safety hazards. Snow covered or iced aerodrome movement areas or aircraft require an initiation of counteractions on time. In order to minimize economic loss and to maintain safety, winter weather situations within an investigation area around an airport have to be detected and forecasted as precisely as possible. At the Department of Transport Meteorology of the German Aerospace Center’s (DLR) Institute of Atmospheric Physics the winter weather nowcasting system WHITE (Winter Hazards In Terminal Environment) has been developed kindly supported by Munich Airport operations. Designed as an automated system WHITE assimilates multiple real-time data sources and assesses problematic winter weather aspects like the differentiation between snow and liquid precipitation, the identification of freezing precipitation and icing plus the rating of surface conditions. The innovative approach of WHITE, combining critical parameters for different predefined winter weather scenarios by means of Fuzzy Logic, classifying hazardous regions and generating winter weather objects, enables the determination of precipitation type and hazard’s intensity.

Large-scale atmospheric flow conditions and sea surface temperatures associated with hazardous winds in Switzerland

The link between hazardous winter winds in Switzerland and the large-scale atmospheric and sea surface temperature (SST) environment in the North Atlantic basin is examined. The analyses cover synoptic, interannual, and decadal time scales and are based on all ensemble members of the Twentieth Century Reanalysis dataset for 1871–2008. On the synoptic time scale, the top ten high wind events in Switzerland are analysed; on longer time scales, the variability of the integrated winter wind loss potential (WLP) in Switzerland is examined. The top ten high wind events were associated with an eastward extension of the extratropical jet, enhanced cyclone frequencies over the North Sea and Scandinavia and reduced cyclone frequencies over the Mediterranean. The events were further accompanied by positive SST anomalies in the East Atlantic and the Mediterranean, and positive lower-tropospheric temperature and atmospheric moisture anomalies over Western and Central Europe. On interannual and decadal time scales, the winter WLP variability was associated with a large-scale atmospheric and SST pattern resembling a southeastward displacement of the winter North Atlantic Oscillation (NAO) pattern. The correlation of the WLP with the NAO and the East Atlantic pattern was positive for most of the 1951–2008 period, and increased with time. The distinct eastward shift of the northern centre of action of the NAO at the end of the twentieth century may explain the improved correlation between the winter NAO variability and the WLP.

A catalog of high-impact windstorms in Switzerland since 1859

Abstract. In recent decades, extremely hazardous windstorms have caused enormous losses to buildings, infrastructure and forests in Switzerland. This has increased societal and scientific interest in the intensity and frequency of historical high-impact storms. However, high-resolution wind data and damage statistics mostly span recent decades only. For this study, we collected quantitative (e.g., volumes of windfall timber, losses relating to buildings) and descriptive (e.g., forestry or insurance reports) information on the impact of historical windstorms. To define windstorm severity, normalized and declustered quantitative data were processed by extreme value statistics. Descriptive information was classified using a conceptual guideline. Validation with independent damage information, as well as comparison with wind measurements and a reanalysis, indicates that the most hazardous winter storms are captured, while too few moderate windstorms are detected. Strong storms in the wind measurements and reanalysis are thus added to the catalog. The final catalog encompasses approximately 240 high-impact windstorms in Switzerland since 1859. It features three robust severity classes and contains eight extreme windstorms. Evidence of high winter storm activity in the early and late 20th century compared to the mid-20th century in both damage and wind data indicates a co-variability of hazard and related damage on decadal timescales.

Considerations on Recent Freezing Phenomena on Bistriţa and Bistricioara Rivers

Abstract It is highly important to have a better knowledge of river systems during the seasons when air temperature drops below freezing point if we consider the difficulties posed to hydrotechnical exploitations and the destruction caused by floods (as a result of ice jam development). The article presents briefly some opinions and hypotheses various researchers have formulated over time on the genesis of ice formations on rivers. Moreover, the article includes several analyses of ice formations developed on the Bistriţa and Bistricioara rivers as wells as hazardous winter phenomena that may cause such ice formations, e.g., ice jams (ice dams). The development of winter-specific phenomena on the two rivers during the winter of 2011 - 2012 is illustrated in pictures, graphs, and maps taken or developed on the basis on data collected in situ during research.

Novel Pattern Detection Algorithm for Monitoring Phase Change of Moisture on Concrete Pavement Using Surface Temperature Data

The presence of snow and ice on the pavement are major winter hazards for roadway traffic safety. Pavement temperature sensors are usually employed as a standard road weather element in many road weather information systems. A novel pattern detection algorithm has been developed to monitor the phase change of moisture on the pavement surface by analyzing a single surface temperature reading. The results of both indoor weather chamber tests and field tests under realistic highway in-service traffic conditions demonstrate that the event of moisture phase changes (e.g., dry, wet, snowy, and icy states) can be detected by converting a complicated raw sensor time history signal into a simpler binary “spike train” time history signal. These spikes can be tuned by the user to detect only the events of interest that are usually entangled with various known and unknown ambient trends in field sensor data. Since the procedures of the developed data processing algorithm are data driven and not limited to specific sensor types or physical problems, the methodology used in this study potentially can be applied widely in many field-monitoring applications.