DataStreme WES Week Five: 4-8 October 2004

• No more major hurricanes forecasted -- Last Friday, Professor William Gray of Colorado State University issued a forecast in which he said that he foresaw no more major hurricanes (Category 3 or higher on the Saffir-Simpson Hurricane Intensity Scale) for the rest of the 2004 North Atlantic hurricane season, which officially runs through 30 November. However, he thought that as many as three more named tropical cyclones (to include tropical storms and hurricanes) could form during the remainder of the season. [USA Today]
• Destruction by Jeanne documented from air -- At the end of last week NOAA posted more than 1200 high-resolution aerial images of the destruction along central Florida's Atlantic coastline caused by Hurricane Jeanne following the hurricane's landfall near Vero Beach one week ago last Saturday night. [NOAA News]
• Florida beaches in bad shape from hurricanes -- State officials in Florida have been assessing the damage caused to state beaches as a consequence of the four hurricanes that made landfall in the state during the last two months. These hurricanes have relocated enormous quantities of sand and the experts have noted that efforts to clean up and restore the beaches will be extremely costly. [USA Today]
• Harmful algae forecast system now operational for Gulf Coast -- The NOAA Administrator, Conrad C. Lautenbacher announced last week that a new operational system became operational last Friday, which would permit the production of twice weekly forecasts of harmful algae blooms in the Gulf of Mexico and Florida coasts, along with assessments of the likely impacts to the environment. [NOAA News]
• West Coast algae bloom sighted -- Scientists from the University of Washington and the Northwest Fisheries Science Center at the end of last week reported that a toxic algae bloom located approximately 15 miles off the Washington State coast had grown to a record 30 mile width. [ENN]
• Gulf "dead zone" shrinking -- Scientists from Texas A & M University and Louisiana State University recently reported that during a research cruise in the northern Gulf of Mexico in August, they found to their surprise that the region of low oxygen and marine losses dubbed the "dead zone" appears to have either moved or disappeared. [EurekAlert!]
• Western lakes in the Southwest continuing to shrink -- The extended five-year drought across the West has caused water levels on many of the major lakes and reservoirs across the region to fall to record levels. These low levels have had an adverse effect on recreation and tourism. [USA Today]
• Flooding rains do not appear a drought-breaker -- The recent heavy rains that produced floods across the Rio Grande Valley of west Texas and helped continue to produce above average precipitation totals since the beginning of this summer do not appear to have offset the cumulative effects of several years of drought, according to National Weather Service personnel. [USA Today]
• Governmental action needed to avert a water crisis -- The general manager of the International Water Management Institute recently warned that governments around the world need to take action to avert a major global water crisis that has deprived as many as one billion of the world's poor of potable water and have caused millions of deaths due to diarrhea. [ENN]
• More curbs placed on cruise ship pollution -- California governor Arnold Schwartzenegger signed legislation late last week that would ban cruise ships with 250 or more passengers from incinerating trash or dumping gray water within three miles of the California coast. [ENN]
• Analyzing the path of drugs in wastewater-- The National Institute of Standards and Technology is running experiments to study the fate of a variety of drugs that enter the nation's wastewater system. [EurekAlert!]
• New center to focus on water use issues -- Arizona State University officials recently announced the creation of the "Decision Center for a Desert City" that will investigate the effects of urban growth in arid regions and investigate the decision processes used to plan and manage finite water resources in such an environment. [EurekAlert!]
• Global and US Hazards/Climate Extremes -- A review and analysis of the global impacts of various weather-related events, including drought, floods and storms during the current month. [NCDC]
• Global Water News Watch -- Other water news sources can be obtained through the SAHRA Project at the University of Arizona [SAHRA Project]
• Earthweek -- Diary of the Planet [earthweek.com] Requires Adobe Acrobat Reader.

Concept of the Week: Artificial Snow

Snow is the essential ingredient for many winter recreational activities including downhill and cross-country skiing, snow boarding, and snowmobiling. No natural snow cover means no cross-country skiing or snowmobiling. But downhill ski hill operators have another option if weather conditions do not provide adequate snow cover-they can generate their own snow. Artificial snow is used to build a base for skiing, refresh snow surfaces, and make skiing possible even during a snow drought, significantly lengthening the ski season. Some ski areas have the equipment to spread artificial snow over 80% or more of their terrain. Whereas snowmaking offers many recreational and economic advantages, some drawbacks stem from altering the local water balance.

Artificial snow is actually tiny particles of ice. Snow makers use specially designed snow guns into which flexible hoses feed compressed air and water separately. A jet of compressed air breaks the stream of water into a fine mist of tiny droplets, which if conditions are favorable, freezes to ice crystals. Expansional cooling of the compressed air as it is emitted through the nozzle of the snow gun and into the atmosphere chills the water droplets. Artificial "snowflakes" settle onto the slopes and mechanized snow groomers then till and spread the accumulated artificial snow evenly over the ski slopes.

Many snowmakers add a special protein (commercially known as Snowmax) to the air/water mix to improve both the quality and quantity of artificial snow. A non-toxic and non-pathogenic strain of a bacterium produces the protein that attracts water and promotes ice crystal formation. Snowmax increases the amount of artificial snow produced at higher temperatures and snowflakes tend to be drier and lighter than other artificial snowflakes.

Ideal weather for snowmaking consists of low air temperature, light winds, and low humidity. Snowmaking is possible even when the air temperature is above 0ºC provided that the relative humidity is sufficiently low that the wet-bulb temperature is below 0ºC. Recall from pages 65-66 in your DataStreme WES Textbook that the wet-bulb temperature is the reading obtained through evaporative cooling when water vaporizes from the wetted bulb of a liquid-in-glass thermometer. Some droplets in the fine water spray (produced by the snow gun) evaporate, tapping latent heat from the air. With sufficient evaporative cooling, the air temperature drops to the wet-bulb reading, that is, to freezing or below, and subsequent water droplets freeze to ice crystals.

The significant water demand for snowmaking may impact the local water balance. In Vermont, for example, snowmaking uses about 2 billion gallons of water per year-equivalent to about one-seventh of the volume of the public water supply. To cover an area measuring 500 m by 60 m with 20 cm (8 in.) of artificial snow requires about 2500 cubic meters (658,000 gallons) of water. Streams are the usual source of water for snowmaking but ski areas are typically located high on hill or mountain slopes where stream flow is normally low, especially in winter. In some cases, dams or holding ponds are constructed to ensure an adequate water supply. Diversion of water for snowmaking may cut the supply of water for users downstream. Water that is stored in the winter snowpack on the ski trails runs off to streams during the spring snowmelt, adding to the normally high spring stream discharge and perhaps increasing the potential for downstream flooding.

Concept of the Week: Questions

1. If the air temperature were above 0ºC, artificial snow can be made if the wet-bulb temperature were [(above) (below)] the freezing point of water.
2. When water droplets evaporate while falling through a layer of relatively dry air, the temperature of the surrounding air [(falls) (rises)].

• 4 October 1869...A great storm struck New England. The storm reportedly was predicted twelve months in advance by a British officer named Saxby. Heavy rains and flooding plagued all of New England, with strong winds and high tides along the coast of New Hampshire and Maine. Canton, CT was deluged with 12.35 inches of rain. (David Ludlum)
• 4 October 1986...Excessive flooding was reported along the Mississippi River and all over the Midwest, from Ohio to the Milk River in Montana. In some places, it was the worst flooding of record. Rainfall totals for the week included 20.07 inches at Hale, KS, nearly 18 inches at Coffeyville and Walnut, KS. (Sandra and TI Richard Sanders - 1987) (Intellicast)
• 5 October 1786...The famous "Pumpkin Flood" occurred on the Delaware and Susquehanna Rivers. Harrisburg, PA reported a river stage of twenty-two feet. The heavy rains culminated a wet season. (David Ludlum)
• 5 October 1972...Heavy rains, mostly the remnants of Tropical Storm Joanne, fell across much of Arizona. It was believed to be the first time in Arizona weather history that a tropical storm entered the state with its circulation still intact. The center was over Flagstaff early on the 7th. (3rd-7th) (The Weather Channel)
• 5-7 October 1999...A storm southeast of New Zealand caused surf to reach heights of 12 feet along the south shores of all the Hawaiian Islands, flooding some roads and parking lots. The lobby of the Kihei Beach Resort on Maui and three ground floor units were flooded. (Accord Weather Calendar)
• 6 October 1967...Canada's 24-hour rainfall record was established at Ucluelet Brynnor Mines on Vancouver Island in British Columbia with 19.24 in. (Accord Weather Calendar)
• 7 October 1737...A furious cyclone in the Bay of Bengal caused a major disaster at the mouth of the Hoogby River near Calcutta, India. As many as 300,000 people were killed, mainly as the result of the storm's forty foot high surge. (Accord Weather Calendar)
• 8 October 1871...Prolonged drought and desiccating winds from the southwest led to the great Chicago fire, the Peshtigo horror, and the Michigan fire holocaust. Fire destroyed more than seventeen thousand buildings killing more than 200 persons in the city of Chicago, while on the same night a fire consumed the town of Peshtigo, WI killing more than 1100 persons. In Wisconsin, a million acres of land were burned, and in Michigan, 2.5 million acres were burned killing 200 persons. "Tornadoes of fire" generated by intense heat caused houses to explode in fire, and burned to death scores of persons seeking refuge in open fields. (David Ludlum) (The Weather Channel)
• 9 October 1903...New York City was deluged with 11.17 in. of rain in 24 hours at Central Park to establish a state record, while 9.40 in. fell at Battery Park. Severe flooding occurred in the Passaic Valley of New Jersey where more than fifteen inches of rain was reported. (David Ludlum) (The Weather Channel) (Intellicast)
• 9 October 1936...The first generator at Boulder Dam, later renamed Hoover Dam, began generating for Los Angeles. From 1939 to 1949, the Hoover power plant with 17 main turbines was the world's largest. (Today in Science)
• 9 October 1967...A cyclone of relatively small dimension with a surface width of only 31 miles hit India's coast at Orissa and moved to the northeast along the coast for 75 miles. As many as 1000 people and 50,000 head of cattle died. A tidal wave in the storm's wake penetrated 16 miles inland. (Accord Weather Calendar)
• 10 October 1973...Fifteen to 20 inch rains deluged north central Oklahoma in thirteen hours producing record flooding. Enid was drenched with 15.68 inches of rain from the nearly stationary thunderstorms, which established a state 24-hour rainfall record. Dover, OK reported 125 of 150 homes damaged by flooding. (David Ludlum) (The Weather Channel)
• 10-16 October 1780...The most deadly Western Hemisphere hurricane on record raged across the Caribbean Sea. "Great Hurricane of 1780" killed 22,000 people on the islands of Martinique, St. Eustatius, and Barbados. Thousands more died at sea. (The Weather Doctor)
• 11 October 1737...Deadly cyclone and storm surge of 42 ft raced up the Hooghly River in India and through the city of Calcutta destroying an estimated 40,000 boats and drowning as many as 300,000 people. (The Weather Doctor)
• 11 October 1846...A very intense hurricane caused great destruction on the Florida Keys. Key West was virtually destroyed with 5 feet of water reported in the city. Fort Taylor was reduced to ruins. (Intellicast)
• 11 October 1954...A deluge of 6.72 inches of rain in 48 hours flooded the Chicago River, causing $10 million in damage in the Chicago area. Unofficial reports indicated as much as 12 inches of rain fell. (9th-11th) (David Ludlum) (The Weather Channel)
• 11-12 October 1995...Heavy rain contributed to flooding along parts of I-75 near Ocala, FL. Five sinkholes up to 10 feet deep and 15 feet wide turned I-75 into a parking lot, as traffic was backed up for more than 5 miles. (Accord Weather Calendar)
• 12 October 1886...A hurricane made landfall between Sabine Pass, TX and Johnson's Bayou, LA. Tidal waves were said to be as high as 2-story buildings. The surge extended 20 miles inland, with 150 people killed. Survivors clung to trees or floated on mattresses. Only two of 100 homes in Sabine Pass were reparable. (Accord Weather Calendar)
• 12 October 1954...Hurricane Hazel pounded Haiti and the island of Hispaniola with winds of 125 mph. Many villages were reported totally destroyed and more than 1000 Haitians die. (The Weather Doctor)
• 12 October 1962...Remnants of Typhoon Freda struck the Pacific Coast of British Columbia's Vancouver Island. Wind speeds at Victoria reached 44 mph with gusts to 87 mph. Seven people died as a result of this storm that also caused $10 million in damage. (The Weather Doctor)
• 12 October 1979...The lowest observed sea-level barometric pressure (870 mb or 25.69 inches of mercury) was recorded near Guam in the western Pacific Ocean at the center of Typhoon Tip. (The Weather Doctor)

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Prepared by AMS WES Central Staff and Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 2004, The American Meteorological Society.