Major growth in some business related uses of climate information

Uses of climate information have grown considerably in the past 15 years as a wide variety of weathersensitive businesses sought to deal effectively with their financial losses and manage risks associated with various weather and climate conditions. Availability of both long-term quality climate data and new technologies has facilitated development of climate-related products by private-sector atmospheric scientists and decision makers. Weather derivatives, now widely used in the energy sector, allow companies to select a financially critical seasonal weather threshold, and, for a price paid to a provider, to obtain financial reparation if this threshold is exceeded. Another new product primarily used by the insurance industry is weather-risk models, which define the potential risks of severe-weather losses across a region where few historical insured loss data exist. Firms develop weather-risk models based on historical storm information combined with a target region’s societal, economic, and physical conditions. Examples of the derivatives and weather-risk models and their uses are presented. Atmospheric scientists who want to participate in the development and use of these new risk-management products will need to broaden their educational experience and develop knowledge and skills in fields such as finance, geography, economics, statistics, and information technology

Lessons from the unusual impacts of an abnormal winter in the USA

Economic impacts from the near record warm and snow-free winter of 2001–2 in the United States were assessed to ascertain their dimensions and relevance to issues like climate prediction and climate change. Unusual impacts resulted and embraced numerous sectors (heating/energy use, construction, tourism, insurance, government, and retail sales). Many outcomes were gains/benefits totalling $19.6 billion, with losses of$8.2 billion. Some economists identified the sizable positive impacts as a factor in the nation’s recovery from an on-going recession stemming from the terrorist attacks on 11 September 2001. Understanding the impacts of such a winter reveals how climate predictions of such conditions could have great utility in minimising the losses and maximising the gains. The results also have relevance to the global warming issue since most climate models project future average winter temperature and snowfall conditions in the United States to be similar to those experienced in 2001–2

Economic impacts and analysis methods of extreme precipitation estimates for eastern Colorado

1986 Summer.Includes bibliographic references.Dams are designed to store water and to insure human safety and as such they must withstand, in their lifetimes, any extreme precipitation event in their drainage basin. Correct estimation of this event is critical because on one hand it must provide an adequate level of safety to not occur, but it must not be any greater than needed since the high costs of dam construction and modifications are directly related to the magnitude of the estimated extreme event. Most frequently the extreme precipitation event is labeled as the Probable Maximum Precipitation, or PMP. National and state concerns over the adequacy of existing dams in the United States as well as increased development of the Front Range led to a federal reassessment and redefinition of new PMP values issued for Colorado in 1984. The study area included the region from the Continental Divide to the 103rd Meridian. Study of these new PMP values and their potential economic impacts in Colorado reveals that an enormous cost will result in Colorado. Techniques for estimating cost of modifications for spillways were developed. Among 162 high risk dams, the estimated total cost for modification was approximately $184 million. The economic value of this precipitation estimate is$9.45 million per inch change of rainfall in this limited study area. In one elevation region, 7000 to 9000 feet, the cost is approximately $15.76 million per inch change of rainfall. Regional cost analyses revealed the South Platte River Division had the greatest costs. Inherent limitations in the PMP procedure and the cost of spillway modifications have made evaluating other alternatives necessary. Special aspects of estimates for extreme precipitation, such as snowmelt runoff versus extreme precipitation events and climate variations were examined. Four methods for estimating extreme precipitation events were evaluated; the traditional PMP, the paleogeological, the cloud/mesoscale dynamic model, and the statistical approaches. A collection of approaches were recommended for Colorado dam design in three elevation regions: the plains, the foothills, and the mountains

Temporal and Spatial Characteristics of Snowstorms in the Contiguous United States

A climatological analysis of snowstorms across the contiguous United States, based on data from 1222 weather stations with data during 1901–2001, defined the spatial and temporal features. The average annual incidence of events creating 15.2 cm or more in 1 or 2 days, which are termed as snowstorms, exhibits great spatial variability. The pattern is latitudinal across most of the eastern half of the United States, averaging 0.1 storm (1 storm per 10 years) in the Deep South, increasing to 2 storms along the Canadian border. This pattern is interrupted by higher averages downwind of the Great Lakes and in the Appalachian Mountains. In the western third of the United States where snow falls, lower-elevation sites average 0.1–2 storms per year, but averages are much higher in the Cascade Range and Rocky Mountains, where 5–30 storms occur per year. Most areas of the United States have had years without snowstorms, but the annual minima are 1 or more storms in high-elevation areas of the West and Northeast. The pattern of annual maxima of storms is similar to the average pattern. The temporal distribution of snowstorms exhibited wide fluctuations during 1901–2000, with downward 100-yr trends in the lower Midwest, South, and West Coast. Upward trends occurred in the upper Midwest, East, and Northeast, and the national trend for 1901–2000 was upward, corresponding to trends in strong cyclonic activity. The peak periods of storm activity in the United States occurred during 1911–20 and 1971–80, and the lowest frequency was in 1931–40. Snowstorms first occur in September in the Rockies, in October in the high plains, in November across most of the United States, and in December in the Deep South. The month with the season’s last storms is December in the South and then shifts northward, with April the last month of snowstorms across most of the United States. Storms occur as late as May and June in the Rockies and Cascades. Snowstorms are most frequent in December downwind of the Great Lakes, with the peak of activity in January for most other areas of the United States

Hydro-meteorological responses to tropical system precipitation in Illinois

This study sought to characterize the impact of tropical system precipitation on streamflow values measured in nine Illinois watersheds and determine whether a predictive model based on antecedent and expected rainfall conditions could be developed. Unlike smaller-scale thunderstorm complexes which are difficult to forecast beyond 24 hours, there is much greater forecast lead time associated with tropical systems. The differences in spatial and temporal scales associated with two types of heavy rain producing storms suggests that hydro-meteorologists have a better opportunity to develop timely regional precipitation and streamflow forecasts as a tropical system approaches Illinois. During a 100-year period (1913-2012) 26 tropical systems were found to have produced an average of an inch or more precipitation within a 24-hour window (i.e., event) in one or more of Illinois’ nine climate divisions. Those climate divisions impacted by an event experienced a significant increase in monthly soil moisture levels as measured by the Palmer Drought Severity Index (PDSI). When pre- versus post-tropical system streamflow (ST) values were compared for the non-event watersheds an increase in ST of less than 50% occurred, while ST changes in watersheds that experienced an event increased by more than 500%. Factors that influenced the magnitude of increase included pre-storm ST conditions (i.e., was ST below, near or above average prior to the event), timing of event (i.e., summer or fall), and total storm precipitation. The predictive ST model, where model output (e.g., post event ST estimates) could be integrated into decision support tools used by those impacted by flooding, was of limited use. Reasons for a lack of success were related to three primary issues, a small sample of events (i.e., 26) in the study, events occurring over a long period (100-years) when changes in land use and agricultural practices altered the surface hydrology (i.e., use of tiles, no-till agriculture, expanding crops in risky environments, etc.), and different surface characteristics (e.g., basin shape and size, soils, geomorphology, etc.) among the nine watersheds. Despite the issues that add complexity to the rainfall to ST relationships over time, those who are tasked with forecasting tropical storm precipitation and related ST values have greater knowledge of how ST values increase and can provide more lead time to regional decision makers in affected watersheds.U.S. Department of the InteriorU.S. Geological SurveyOpe

Economic impacts and analysis methods of extreme precipitation estimates for eastern Colorado

August 1986.Includes bibliographical references (pages 56-59).Dams are designed to store water and to ensure human safety and as such they must withstand, in their lifetimes, any extreme precipitation event in their drainage basin. Correct estimation of this event is critical because on one hand it must provide an adequate level of safety to not occur, but it must not be any greater than needed since the high costs of dam construction and modifications are directly related to the magnitude of the estimated extreme event. Most frequently the extreme precipitation event is labeled as the Probable Maximum Precipitation, or PMP. National and state concerns over the adequacy of existing dams in the United States as well as increased development of the Front Range led to state dam risk reclassification and federal redefinition of new PMP values issued for Colorado in 1984. The study area included the region from the Continental Divide to the 103rd Meridian. Study of the implementation of PMP values and their potential economic impacts in Colorado reveals that an enormous cost will result in Colorado. Techniques for estimating cost of modifications for spillways were developed. Among 162 high risk dams, the estimated total cost for modification was approximately $184 million. The economic value of this precipitation estimate is$9.45 million per inch change of rainfall in this limited study area. In one elevation region, 7000 to 9000 feet, the costs is approximately $15.76 million per inch change of rainfall. Regional cost analyses revealed the South Platte River Division had the greatest costs. Inherent limitations in the PMP procedure and the cost of spillway modifications have made evaluating other alternatives necessary. Special aspects of estimates for extreme precipitation, such as snowmelt runoff versus extreme precipitation events and climate variations were examined. Four methods for estimating extreme precipitation events were evaluated; the traditional PMP, the paleogeological, the cloud/mesoscale dynamic model, and the statistical approaches. A collection of approaches were recommended for Colorado dam design in three elevation regions: the plains, the foothills, and the mountains.Supported by NOAA under Grant No. NA-85-RAH-05045 through CIRA

Climatology of Surface Cyclone Tracks Associated with Large Central and Eastern U.S. Snowstorms, 1950–2000

The 241 largest snowstorms over the eastern two-thirds of the United States during 1950–2000 exhibited considerable temporal variability ranging from 1 storm in three winters to 10 storms in 1993/94. The peak decadal frequency was 55 storms (1950s), and the minimum was 45 storms (1970s and 1980s). The east– north-central region experienced the greatest number of large snowstorms (148) followed by the west– north-central (136) and central (133) regions. Regional trends were different. Assessment of surface cyclone tracks associated with the large snowstorms identified three primary tracks: one was located from the leeward side of the south-central Rocky Mountains east-northeast toward the Great Lakes; a second was from the lower Mississippi River basin northeastward toward the Great Lakes; and a third was along the coastal mid-Atlantic region northeast toward Maine. Temporal differences in the frequency of certain surface cyclone tracks were related to the decadal trends in regional large snowstorm occurrence. The minimum surface pressure associated with these storms ranged from 959 to 1013 hPa with more than 67% of all storms having a minimum surface pressure between 980 and 999 hPa. The average orthogonal distance from the storm track to the heavy snow region was 201 km. The average rate of cyclone movement ranged from less than 483 to more than 1930 km day 1, with more than 57% of storms moving between 805 and 1287 km day 1

Changes in the Frequency of Extreme Warm-Season Surface Dewpoints in Northeastern Illinois: Implications for Cooling-System Design and Operation

Warm-season (1 May–30 September) hourly dewpoint data were examined for temporal changes at two weather stations in northeastern Illinois during a 42-yr period (1959–2000). This area has dense population (greater than 8 million), and shifts to more or less atmospheric moisture have major implications on cooling demands. The 42-yr period was analyzed as two separate arbitrarily chosen equally sized periods, the early (1959–79) and the later (1980–2000) periods. Analyses of data from Chicago’s O’Hare International Airport and the Greater Rockford Airport showed a statistically significant increase in the number of hours with dewpoints greater than or equal to 248C (an important cooling-plant threshold) in the latter period. Examination of heat-wave periods indicated that later (especially 1995 and after) heat waves contained many more extreme dewpoint values. These increases in extreme dewpoint characteristics in northeastern Illinois affect the operation of, and suggest shifts in design criteria for, air-conditioning systems and affect summer peak electrical loads

Record Winter Storms in Illinois, 1977-1978

The Midwest, including Illinois, experienced in 1977-1978 its most severe winter since weather records began in the early Nineteenth Century. Illinois had a record-breaking number of 18 severe winter storms; 4 such storms is normal. The record winter began with 3 snowstorms in late November and ended with an extremely damaging ice storm in late March. Unusual snow patterns occurred with several storms and they lasted much longer than usual. Weather conditions (low pressure centers) producing many of the storms were more often of Canadian origin than usual, and these lows had lower pressure and moved slower than normal, resulting in higher surface winds and longer lasting and hence more severe storms. Cold temperatures along with frequent snows resulted in record long lasting snow cover with up to 120 days with ≥1 inch cover in northern Illinois and 90 days in southern Illinois. The storms led to 62 deaths and more than 2000 injuries. Utilities, communication systems, and transportation suffered great losses, though railroads benefited with increased use and helicopters and snowmobiles proved valuable in rescue service. Local, state, and federal institutions were beset with enormous and costly problems including care of roads and lost taxable income due to absenteeism.publishedpeer reviewedOpe

Illinois Third Consecutive Severe Winter: 1978-1979

For the first time since records began in the 1880s, a third consecutive severe winter occurred in Illinois in 1978-1979. Seventeen major winter storms, the state's record coldest January-February (15.9°F, or 14° below normal), and record snow depths (≥40 inches) gave the winter of 1978-1979 a rank as the second worst statewide for Illinois, exceeded only by the prior winter of 1977-1978 (18 storms, coldest statewide December-March, record longest lasting snow cover). The 1978-1979 winter was the worst on record in the northern fourth of the state, where snowfall averaged 68 inches and point record totals of up to 100 inches occurred. Average snowfall for the state was 42.8 inches, or 23.3 inches above normal. In other parts of the state snowfall averages were: 40 inches (20 above) north central, 32 inches (12 above) south central, and 31 inches (22 above) southern Illinois. Severe storms began in late November and extended into March; fourteen storms also had freezing rain, but ice was moderately severe in only two cases. High wind and blizzard conditions occurred in only three storms (compared with eight in prior winter), suggesting a lack of extremely deep low pressure centers. The 1978-1979 winter had a myriad of socio-economic impacts, the most serious ones in the Chicago metropolitan area. Surface and air transportation was hardest hit, but utilities, businesses and industries, institutions, farm operations, and many human activities were also affected. Ten deaths and at least 60 serious injuries were attributed to the storms.publishedpeer reviewedOpe